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Campaigns group missions around a shared mathematical goal. Each one tracks a quantity, such as an upper or lower bound. Have a good candidate in mind? Ping us on Slack, Zulip, or WeChat.

Quantum Max-Cut

Quantum Max-Cut asks for the largest eigenvalue of a graph's quantum spin Hamiltonian. For a graph GGG with nonnegative rational edge weights, write

HG=∑i<jwij(I−SWAPij),OPT(G)=λmax⁡(HG).H_G=\sum_{i<j}w_{ij}(I-\mathrm{SWAP}_{ij}),\qquad\mathrm{OPT}(G)=\lambda_{\max}(H_G).HG​=i<j∑​wij​(I−SWAPij​),OPT(G)=λmax​(HG​).

This campaign tracks expected approximation ratios for classical polynomial-time energy estimation. One uniform randomized classical algorithm must work for every input graph. For each fixed GGG, let RRR be the algorithm's internal fair random bits, and let v(G,R)v(G,R)v(G,R) be its nonnegative rational output. A ratio α\alphaα requires

0≤v(G,R)≤OPT(G)for every random outcome R,0\le v(G,R)\le\mathrm{OPT}(G)\quad\text{for every random outcome }R,0≤v(G,R)≤OPT(G)for every random outcome R, ER[v(G,R)]≥α OPT(G).\mathbb E_R[v(G,R)]\ge\alpha\,\mathrm{OPT}(G).ER​[v(G,R)]≥αOPT(G).

The expectation averages the algorithm's internal randomness on a fixed graph. Its running time is bounded by a polynomial on every run. Higher ratios are better.

See the Quantum MaxCut reference for the problem definition and research context.

≥ 0.5Formalized record→≥ 0.526Open frontier
3 provers on it3 of 8 missions formalized

Block Sensitivity vs. Sensitivity

How much larger can block sensitivity be than sensitivity for a total Boolean function?

For a total Boolean function f:{0,1}n→{0,1}f:\{0,1\}^n\to\{0,1\}f:{0,1}n→{0,1}, a block of coordinates is sensitive at xxx if flipping every bit in that block changes f(x)f(x)f(x). Let s(f,x)s(f,x)s(f,x) count sensitive singletons and bs(f,x)bs(f,x)bs(f,x) be the maximum number of pairwise disjoint sensitive blocks. Define s(f)=max⁡xs(f,x)s(f)=\max_x s(f,x)s(f)=maxx​s(f,x) and bs(f)=max⁡xbs(f,x)bs(f)=\max_x bs(f,x)bs(f)=maxx​bs(f,x).

This campaign seeks larger exponents α\alphaα for which there exists an infinite family of total Boolean functions fk:{0,1}nk→{0,1}f_k:\{0,1\}^{n_k}\to\{0,1\}fk​:{0,1}nk​→{0,1}, indexed by k=1,2,…k=1,2,\ldotsk=1,2,…, satisfying

s(fk)→∞,bs(fk)≥s(fk)α−o(1)as k→∞.s(f_k)\to\infty,\qquad bs(f_k)\ge s(f_k)^{\alpha-o(1)}\quad\text{as }k\to\infty.s(fk​)→∞,bs(fk​)≥s(fk​)α−o(1)as k→∞.

Here o(1)o(1)o(1) denotes a quantity tending to zero as k→∞k\to\inftyk→∞. Higher is better. The classical exponent is 222, and Huang's bound gives a ceiling of 444.

OpenAI's construction achieves an exponent strictly greater than 222.

One sufficient way to establish an exponent α\alphaα is to find a single total Boolean function fff with s(f)>1s(f)>1s(f)>1 and bs(f)≥s(f)αbs(f)\ge s(f)^\alphabs(f)≥s(f)α. Input and output normalization followed by self-composition then yields the required asymptotic family.

≥ 2.13981Formalized record→≥ 2.15Open frontier
11 provers on it22 of 23 missions formalized

Integer Multiplication Below n log n

Turn proposed improvements to integer multiplication into complete Lean proofs, and push the exponent saving further.

Harvey and van der Hoeven established an O(nlog⁡n)O(n\log n)O(nlogn) algorithm in 2021. This campaign builds on that foundation, the OpenAI manuscript, and subsequent community constructions to pursue a strict asymptotic improvement.

For two nnn-bit integers, the target is

T(n)=O ⁣(n L(n)1−κ),L(n)=max⁡(⌈log⁡2n⌉,1).T(n)=O\!\left(n\,L(n)^{1-\kappa}\right),\qquad L(n)=\max(\lceil\log_2 n\rceil,1).T(n)=O(nL(n)1−κ),L(n)=max(⌈log2​n⌉,1).

A positive κ\kappaκ beats nlog⁡nn\log nnlogn asymptotically; larger κ\kappaκ is better. Every entry must exhibit one deterministic multitape Turing machine, with a fixed finite alphabet and tape count, that computes the exact product at every positive input length and meets the eventual worst-case time bound. The tracked number measures an asymptotic exponent saving.

≥ 3.6 × 10−5Formalized record→≥ 5.1 × 10−5Open frontier
8 provers on it4 of 7 missions formalized

3SUM Exponent

Classical algorithms solve 3SUM in O(n2)O(n^2)O(n2) time. In a 2026 breakthrough, Alman and Vassilevska Williams gave a deterministic O(n1.9992)O(n^{1.9992})O(n1.9992) algorithm, refuting the integer 3SUM hypothesis. How low can the exponent go?

Building on existing Lean formalizations, this campaign tracks upper bounds for 3SUM on polynomially bounded integers, using a word RAM with O(log⁡n)O(\log n)O(logn)-bit words, and pursues smaller exponents.

≤ 1.960614Formalized record→≤ 1.9202796Open frontier
4 provers on it7 of 8 missions formalized

All-Pairs Shortest Paths (APSP) Exponent

Classical algorithms solve all-pairs shortest paths in O(n3)O(n^3)O(n3) time. In a 2026 breakthrough, Alman and Vassilevska Williams refuted the APSP conjecture with a deterministic O(n2.99942)O(n^{2.99942})O(n2.99942) algorithm. How low can the exponent go?

Building on existing Lean formalizations, this campaign tracks upper bounds for exact APSP and pursues smaller exponents.

≤ 2.995561Formalized record
3 provers on it5 of 5 missions formalized

The irrationality measure of π

The irrationality measure of π quantifies how closely rational numbers can approximate it. This campaign seeks formal proofs of sharper upper bounds, starting with Mahler’s bound of 42.

≤ 2Formalized record
19 provers on it9 of 9 missions formalized

Sharp diagonal Hlawka constant

The sharp Hlawka inequality for Schatten ppp-norms is a cousin of the triangle inequality: it relates the norms of three matrices to the norms of their pairwise sums and their total sum. For complex diagonal matrices, an exact formula for the best possible comparison constant has been proved in Lean for every real p≥256p\ge256p≥256. We conjecture that the same formula holds for all p≥2p\ge2p≥2.

What is the smallest cutoff p′p'p′ for which this formula holds for every real p≥p′p\ge p'p≥p′?

References:

  • Wolfram MathWorld, Hlawka's Inequality.
  • Audenaert and Kittaneh, Problems and Conjectures in Matrix and Operator Inequalities, §8.2 (2017).
  • Marinescu and Niculescu, A New Look at the Hornich–Hlawka Inequality (2025).
  • Analytic argument for p≥90p\ge90p≥90, awaiting formalization in Lean.
≤ 4Formalized record→≤ 2Open frontier
8 provers on it17 of 18 missions formalized

Odd numbers as sums of primes

Is every odd number a sum of kkk primes? This campaign tracks formalized proofs of the smallest kkk that suffices.

Schnirelmann (1930) showed some finite kkk works. Vinogradov (1937) showed that three is enough for all sufficiently large odd numbers. Tao (2012) proved k=5k = 5k=5 unconditionally. Helfgott (2013) proved that every odd number greater than 555 is a sum of three primes, though the proof is still unrefereed. Ideally, we can formalize this statement here. Note that three is optimal: 272727 is neither prime nor 222 + prime.

≤ 19Formalized record→≤ 5Open frontier
42 provers on it17 of 19 missions formalized

Matrix multiplication exponent

Schoolbook matrix multiplication takes n3n^3n3 operations. The exponent ω\omegaω is the infimum of all τ\tauτ such that two n×nn \times nn×n matrices can be multiplied in O(nτ)O(n^{\tau})O(nτ) arithmetic operations; trivially ω≥2\omega \geq 2ω≥2, and ω=2\omega = 2ω=2 is conjectured but open.

Strassen gave the first nontrivial bound, ω<2.81\omega < 2.81ω<2.81, in 1969, and introduced the laser method in 1986 to reach ω<2.48\omega < 2.48ω<2.48. Coppersmith and Winograd's 1990 bound of 2.3762.3762.376 stood for two decades. Every subsequent improvement comes from analyzing higher tensor powers of their construction with refined laser-method variants. That line reached ω<2.371339\omega < 2.371339ω<2.371339 in 2025, and the current record is ω<2.371177\omega < 2.371177ω<2.371177, from August 2026. See Computational complexity of matrix multiplication for the full table. Can we formalize these results and even improve on them?

≤ 2.25Formalized record
16 provers on it9 of 9 missions formalized

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Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions, with reuse governed by our licensing terms.

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Algorithmic Game TheoryConvex OptimizationEconomics+1·Captain: mikedeng1

Constrained Information Design: The Value of an Information Design Problem with Equality and Inequality Constraints Equals the Concave Hull of the Constraint-Modified Objective at the PriorResearch Paper

Motivation

In information design (Bayesian persuasion), a designer commits to a signal about an unknown state, and every signal induces a distribution over the receiver's posterior beliefs. Kamenica and Gentzkow (2011) showed that the distributions a signal can induce are exactly the Bayes-plausible ones, those whose mean posterior is the prior, and that the designer's optimal value is the concave hull (concavification) of the designer's objective, evaluated at the prior. This reduces the design problem to a computation in convex analysis, and it is the basic tool of the information design literature.

Many applications add constraints on the distribution of posteriors: a capacity or cost constraint on information (rational inattention), participation or incentive constraints when the designer is a mechanism designer with limited commitment, or a bound on the probability of a given action. Le Treust and Tomala (2019) treated one inequality constraint for finitely supported distributions. Doval and Skreta (arXiv:1811.03588v3, Mathematics of Operations Research, 2024) allow any finite number of inequality and equality constraints, and an arbitrary Borel distribution over posteriors. Their first main result, Theorem 3.1, shows that the value is still a concave hull, of a function of more variables.

Setting

Let Ω={ω1,…,ωN}\Omega = \{\omega_1, \dots, \omega_N\}Ω={ω1​,…,ωN​} be a finite set of states and Δ(Ω)⊆RN\Delta(\Omega) \subseteq \mathbb R^NΔ(Ω)⊆RN the simplex of beliefs. The data are measurable functions on Δ(Ω)\Delta(\Omega)Δ(Ω): an objective fff, III inequality constraint functions gˉI=(gˉ1,…,gˉI)\bar g_I = (\bar g_1, \dots, \bar g_I)gˉ​I​=(gˉ​1​,…,gˉ​I​) and EEE equality constraint functions gˉE=(gˉI+1,…,gˉI+E)\bar g_E = (\bar g_{I+1}, \dots, \bar g_{I+E})gˉ​E​=(gˉ​I+1​,…,gˉ​I+E​), with I,E≥0I, E \ge 0I,E≥0.

For a prior μ0\mu_0μ0​, Δμ0(Δ(Ω))\Delta_{\mu_0}(\Delta(\Omega))Δμ0​​(Δ(Ω)) is the set of Borel probability measures τ\tauτ on Δ(Ω)\Delta(\Omega)Δ(Ω) with mean μ0\mu_0μ0​. The constrained information design problem (CID) at a parameter (μ0,γ)∈RN+I+E(\mu_0, \gamma) \in \mathbb R^{N+I+E}(μ0​,γ)∈RN+I+E, γ=(γI,γE)\gamma = (\gamma_I, \gamma_E)γ=(γI​,γE​), is

V(μ0,γ)=sup⁡τ∈Δμ0(Δ(Ω))Eτ[f(μ)]s.t.Eτ[gˉI(μ)]≥γI,  Eτ[gˉE(μ)]=γE,V(\mu_0, \gamma) = \sup_{\tau \in \Delta_{\mu_0}(\Delta(\Omega))} \mathbb E_\tau[f(\mu)] \quad\text{s.t.}\quad \mathbb E_\tau[\bar g_I(\mu)] \ge \gamma_I,\ \ \mathbb E_\tau[\bar g_E(\mu)] = \gamma_E,V(μ0​,γ)=τ∈Δμ0​​(Δ(Ω))sup​Eτ​[f(μ)]s.t.Eτ​[gˉ​I​(μ)]≥γI​,  Eτ​[gˉ​E​(μ)]=γE​,

component-wise, with V=−∞V = -\inftyV=−∞ when no τ\tauτ is feasible. The feasibility set F\mathcal FF (Definition 2.2) is the set of (μ,γ~)(\mu, \tilde\gamma)(μ,γ~​) at which (CID) is feasible.

The pointwise set C={(μ,γ~)∈Δ(Ω)×RI+E:gˉI(μ)≥γ~I, gˉE(μ)=γ~E}C = \{(\mu, \tilde\gamma) \in \Delta(\Omega) \times \mathbb R^{I+E} : \bar g_I(\mu) \ge \tilde\gamma_I,\ \bar g_E(\mu) = \tilde\gamma_E\}C={(μ,γ~​)∈Δ(Ω)×RI+E:gˉ​I​(μ)≥γ~​I​, gˉ​E​(μ)=γ~​E​} collects the parameters at which the constraints hold for the degenerate distribution at μ\muμ. The modified objective (3.1) is

fgˉ(μ,γ~)=f(μ)−δ(μ,γ~∣C),f^{\bar g}(\mu, \tilde\gamma) = f(\mu) - \delta(\mu, \tilde\gamma \mid C),fgˉ​(μ,γ~​)=f(μ)−δ(μ,γ~​∣C),

equal to f(μ)f(\mu)f(μ) on CCC and −∞-\infty−∞ off CCC. For a function hhh on RD\mathbb R^DRD, the hypograph is hypo⁡h={(x,y)∈RD+1:y≤h(x)}\operatorname{hypo} h = \{(x, y) \in \mathbb R^{D+1} : y \le h(x)\}hypoh={(x,y)∈RD+1:y≤h(x)} and the concave hull (Definition 2.1) is

(cav⁡h)(x)=sup⁡{y∈R:(x,y)∈conv⁡(hypo⁡h)}.(\operatorname{cav} h)(x) = \sup\{y \in \mathbb R : (x, y) \in \operatorname{conv}(\operatorname{hypo} h)\}.(cavh)(x)=sup{y∈R:(x,y)∈conv(hypoh)}.

In the Lean development these are IsBayesPlausible, IsConstraintFeasible, value, feasibleSet, pointwiseSet, modObj, hypo and cav, in the namespace ConstrInfoDesign.Cav.

Formalization targets

Goal: Theorem 3.1 (p. 7)

For every (μ0,γ)∈RN+I+E(\mu_0, \gamma) \in \mathbb R^{N+I+E}(μ0​,γ)∈RN+I+E,

V(μ0,γ)=cav⁡fgˉ(μ0,γ).(3.2)V(\mu_0, \gamma) = \operatorname{cav} f^{\bar g}(\mu_0, \gamma). \tag{3.2}V(μ0​,γ)=cavfgˉ​(μ0​,γ).(3.2)

The statement fixes no constants and assumes nothing beyond measurability; it covers infeasible parameters, where both sides are −∞-\infty−∞, and unbounded objectives, where both sides may be +∞+\infty+∞.

Milestones (Appendix A, pp. 24–25)

  1. Rubin–Wesler step (proof of Proposition A.1): for τ∈Δμ0(Δ(Ω))\tau \in \Delta_{\mu_0}(\Delta(\Omega))τ∈Δμ0​​(Δ(Ω)) with f,gˉf, \bar gf,gˉ​ integrable, (μ0,Eτf,Eτgˉ)∈conv⁡{(μ,f(μ),gˉ(μ)):μ∈supp⁡τ}(\mu_0, \mathbb E_\tau f, \mathbb E_\tau \bar g) \in \operatorname{conv}\{(\mu, f(\mu), \bar g(\mu)) : \mu \in \operatorname{supp}\tau\}(μ0​,Eτ​f,Eτ​gˉ​)∈conv{(μ,f(μ),gˉ​(μ)):μ∈suppτ}.
  2. Proposition A.1: every feasible τ\tauτ can be replaced by a finitely supported τ⋆\tau^\starτ⋆ with the same mean and the same expectations of (f,gˉ)(f, \bar g)(f,gˉ​).
  3. Lemma A.1: F=conv⁡C\mathcal F = \operatorname{conv} CF=convC.
  4. Proof of Theorem 3.1, first step: off F\mathcal FF, cav⁡fgˉ=V=−∞\operatorname{cav} f^{\bar g} = V = -\inftycavfgˉ​=V=−∞.
  5. Proposition A.2 (Rockafellar, Corollary 17.1.5): (cav⁡h)(x)=sup⁡{∑m≤Mλmh(xm):xm∈dom⁡h, λ∈Δx, M≤D+1}(\operatorname{cav} h)(x) = \sup\{\sum_{m \le M} \lambda_m h(x_m) : x_m \in \operatorname{dom} h,\ \lambda \in \Delta_x,\ M \le D + 1\}(cavh)(x)=sup{∑m≤M​λm​h(xm​):xm​∈domh, λ∈Δx​, M≤D+1}.

Significance

Theorem 3.1 gives the value function of (CID) in closed form as a single concave hull. Its consequences in the paper are a bound N+I+EN + I + EN+I+E on the number of posteriors an optimal design needs (Corollary 3.1), a refinement to N+B+EN + B + EN+B+E with BBB binding constraints (Corollary 3.2), and, combined with Lagrangian duality, the characterization of optimal designs in applications such as mechanism design with limited commitment and persuasion of a privately informed receiver. The result also explains when the feasibility set is the convex hull of the pointwise set (Lemma A.1), which is the geometric reason the constrained problem behaves like an unconstrained one in N+I+EN + I + EN+I+E coordinates.

The result is proved in the paper; to the best of current knowledge none of it is formalized. Mathlib has convex hulls, Carathéodory's theorem, measures, supports and Bochner integrals, but neither the concavification theorem of Kamenica and Gentzkow nor the Rubin–Wesler theorem that the mean of an integrable random vector lies in the convex hull (not only its closure) of a set carrying it. A complete development would give machine-checked versions of both, reusable by any formalization of Bayesian persuasion with finitely many states.

Difficulty

The obvious argument for V≤cav⁡fgˉV \le \operatorname{cav} f^{\bar g}V≤cavfgˉ​ says that the mean of the vector (μ,f(μ),gˉ(μ))(\mu, f(\mu), \bar g(\mu))(μ,f(μ),gˉ​(μ)) under τ\tauτ lies in the convex hull of its range. Mathlib's tools (Convex.integral_mem) only give membership in a closed convex set, and the range of an integrable, possibly unbounded and discontinuous fff is not closed; the closure gives the concave closure of fgˉf^{\bar g}fgˉ​, which differs from the concave hull on the boundary of its domain (Example D.1 of the paper). The Rubin–Wesler theorem closes this gap, but it needs its own argument by induction on dimension.

In Proposition A.2, Carathéodory's theorem in RD+1\mathbb R^{D+1}RD+1 gives D+2D + 2D+2 points of the hypograph; the claimed bound D+1D + 1D+1 needs the extra observation that a point of the hypograph can be moved up to the graph. The remaining steps are bookkeeping in the extended reals: shifting thresholds so that each point of a convex combination lies in CCC, and approximation arguments when the suprema are infinite.

Formalization scope

States are Fin N; beliefs are points of Fin N → ℝ and Δ(Ω)\Delta(\Omega)Δ(Ω) is stdSimplex ℝ (Fin N). The parameter space RN+I+E\mathbb R^{N+I+E}RN+I+E is the product (Fin N → ℝ) × ((Fin I → ℝ) × (Fin E → ℝ)). The functions fff, gˉk\bar g_kgˉ​k​ are total on Fin N → ℝ; their values off the simplex never matter. A distribution over posteriors is a Borel probability measure on Fin N → ℝ that gives the complement of the simplex measure zero, and its mean is the Bochner integral of the identity.

Conventions committed to:

  • VVV, fgˉf^{\bar g}fgˉ​ and cav take values in EReal; suprema are sSup in EReal, so the empty supremum is −∞-\infty−∞.
  • The choice set of (CID) is all such measures, not only finitely supported ones.
  • Every admissible τ\tauτ must make fff and each gˉk\bar g_kgˉ​k​ integrable. The paper leaves this implicit; it is needed because Lean's integral of a non-integrable function is 000. Theorem 3.1 holds unchanged with this convention.
  • Proposition A.1 states the mean μ0\mu_0μ0​ of τ⋆\tau^\starτ⋆ explicitly (the page leaves it implicit).
  • Proposition A.2 is stated for hhh valued in [−∞,+∞)[-\infty, +\infty)[−∞,+∞) on any finite-dimensional real vector space of dimension DDD, because the paper applies it to fgˉf^{\bar g}fgˉ​, which takes the value −∞-\infty−∞.
  • No upper semicontinuity is assumed: Theorem 3.1 does not use the paper's Assumptions fff and gˉ\bar ggˉ​.

Trivializing formalizations are ruled out: VVV is not taken over finitely supported distributions only (which would make Proposition A.1 empty), cav is Definition 2.1 and not the sum formula of Proposition A.2, F\mathcal FF is Definition 2.2 and not conv⁡C\operatorname{conv} CconvC, integrals of non-integrable maps are excluded rather than counted as 000, and no supremum is taken in R\mathbb RR.

The development needs the Rubin–Wesler theorem in finite dimensions, a Carathéodory variant for hypographs, and the finite-dimensional facts that a measure on a second-countable space is carried by its support and that finite sums of Dirac masses are probability measures with the expected integrals. The Rubin–Wesler theorem and Proposition A.2 are reusable beyond this mission. Proofs of the milestones and of the goal, and alternative arguments, are welcome.

Selected references

  • L. Doval and V. Skreta, Constrained Information Design, Mathematics of Operations Research, 2024; held as arXiv:1811.03588v3, 2022. https://arxiv.org/abs/1811.03588
  • E. Kamenica and M. Gentzkow, Bayesian Persuasion, American Economic Review 101(6), 2011. https://doi.org/10.1257/aer.101.6.2590
  • M. Le Treust and T. Tomala, Persuasion with limited communication capacity, Journal of Economic Theory 184, 104940, 2019. https://doi.org/10.1016/j.jet.2019.104940
  • H. Rubin and O. Wesler, A note on convexity in Euclidean n-space, Proceedings of the American Mathematical Society 9, 522–523, 1958. https://www.ams.org/journals/proc/1958-009-04/
  • R. T. Rockafellar, Convex Analysis, Princeton University Press, 1970. https://doi.org/10.1515/9781400873173
7 thms1 active userReviewed
EconomicsProbabilityStatistics·Captain: mikedeng1

The Distortion in Prices Due to Passive Investing: Market Indexing Leaves the Price Efficiency of the Market Portfolio Unchanged and Erodes That of Every Other Portfolio at an Increasing RateResearch Paper

Motivation

Passive funds hold a market index rather than selecting individual stocks. In the model of Baruch and Zhang (2022), this difference matters for what prices reveal. An investor who studies individual stocks can bring information about their payoffs into trading; an investor restricted to the market portfolio cannot make the same stock-by-stock trades. The paper asks how the mix of these investors changes the information about future asset payoffs that can be inferred from market prices. Its answer separates the market portfolio from every other stock portfolio: indexing preserves the former's price efficiency while reducing the latter's, at an increasing rate. This mission targets that price-efficiency result, Theorem 3 on p. 6226.

The question matters to asset-pricing models that use prices as information. A price can be informative even when it is affected by many other forces; here the paper gives a controlled Gaussian economy in which the effect of replacing active investors with indexers can be isolated. The target is a theorem about conditional variances, not an empirical estimate of the effect of real index funds. The equilibrium interpretation comes from the paper's earlier price construction; the formal statements here use the public statistic that the paper proves equivalent for this purpose (15)–(16), p. 6224.

Setting

There are nnn risky assets and mmm investors. The random payoff vector is v∈Rnv\in\mathbb R^nv∈Rn, with multivariate normal law N(μv,Σvv)N(\mu_v,\Sigma_{vv})N(μv​,Σvv​). Investor kkk sees a private signal sk=v+εks_k=v+\varepsilon_ksk​=v+εk​, where εk∼N(0,Σεε)\varepsilon_k\sim N(0,\Sigma_{\varepsilon\varepsilon})εk​∼N(0,Σεε​). The payoff and all noise vectors are mutually independent, and the two covariance matrices are positive definite. A stock portfolio x∈Rnx\in\mathbb R^nx∈Rn pays x′vx'vx′v. The all-ones vector 1\mathbf11 is the market portfolio. These are the assumptions and terms introduced in §2, p. 6221.

The investors are partitioned into indexers III, who hold the market portfolio, and nonindexers NININI. Both kinds are present: 1≤∣NI∣<m1\le |NI|<m1≤∣NI∣<m, with ∣I∣=m−∣NI∣|I|=m-|NI|∣I∣=m−∣NI∣ p. 6222. Equation (3) sets g=(mΣvv+Σεε)−1Σvv1g=(m\Sigma_{vv}+\Sigma_{\varepsilon\varepsilon})^{-1}\Sigma_{vv}\mathbf1g=(mΣvv​+Σεε​)−1Σvv​1. Equation (4) combines the nonindexers' average signal and a scalar statistic of all signals into the public statistic

yNI=(1∣NI∣∑k∈NIsk,g′∑k=1msk).y_{NI}=\left(\frac1{|NI|}\sum_{k\in NI}s_k,\quad g'\sum_{k=1}^{m}s_k\right).yNI​=(∣NI∣1​k∈NI∑​sk​,g′k=1∑m​sk​).

The first component has nnn coordinates; the second has one. The paper identifies the conditional variance given this statistic with the variance given equilibrium prices (16), p. 6224. In this mission, Vx(NI)V_x(NI)Vx​(NI) means the conditional variance of x′vx'vx′v given σ(yNI)\sigma(y_{NI})σ(yNI​). It is initially a random variable, and equation (20) asserts that it is almost surely a deterministic matrix expression under the Gaussian model.

Formalization targets

The goal is Theorem 3, p. 6226, stated for all admissible nonindexer sets on the same probability space. For any real ccc, market-portfolio multiples have unchanged conditional variance:

x=c1⟹Vx(NI)=Vx(NI′)almost surely.x=c\mathbf1\quad\Longrightarrow\quad V_x(NI)=V_x(NI')\quad\text{almost surely}.x=c1⟹Vx​(NI)=Vx​(NI′)almost surely.

For every other portfolio, fewer nonindexers, equivalently more indexers, strictly raise conditional variance. The rate also grows: whenever ∣NI1∣=∣NI2∣+1|NI_1|=|NI_2|+1∣NI1​∣=∣NI2​∣+1 and ∣NI2∣=∣NI3∣+1|NI_2|=|NI_3|+1∣NI2​∣=∣NI3​∣+1,

Vx(NI1)<Vx(NI2)<Vx(NI3),Vx(NI2)−Vx(NI1)<Vx(NI3)−Vx(NI2)almost surely.V_x(NI_1)<V_x(NI_2)<V_x(NI_3),\qquad V_x(NI_2)-V_x(NI_1)<V_x(NI_3)-V_x(NI_2) \quad\text{almost surely}.Vx​(NI1​)<Vx​(NI2​)<Vx​(NI3​),Vx​(NI2​)−Vx​(NI1​)<Vx​(NI3​)−Vx​(NI2​)almost surely.

The six milestones are the identities and statements used in the paper's development: the cross-covariance Σvy\Sigma_{vy}Σvy​ in (7), the covariance Σyy\Sigma_{yy}Σyy​ of yyy in (8), Gaussian conditioning in (20), the characterization of market portfolios in Lemma 2, the first derivative in (21), and the second-derivative conclusion in §6.1, p. 6227. They make the model-to-goal path explicit without changing the goal's three clauses.

Significance

The result specifies which price information survives a shift toward passive investing in this economy. It says that market-portfolio payoff information is preserved while information about every portfolio outside the span of 1\mathbf11 is lost, with an accelerating loss across successive increases in indexer count. The distinction is used later in the paper to discuss asset-price comovement and a conditional CAPM measure §6.2–6.3, pp. 6227–6228.

Baruch and Zhang proved the theorem in 2022. The formalization work is to represent their Gaussian model, its public statistic, the conditional-variance identity, and the comparative-statics claims in Lean, then supply machine-checked proofs. The current proposal contains checked statements and definitions with open theorem proofs; it does not claim that those proofs already exist. The model interface and covariance identities could also support later formalizations of the paper's price and comovement results.

Difficulty

The target compares conditional variances arising from different information sets. Their equality or ordering cannot be read directly from the definitions of conditional expectation. The Gaussian assumption turns the conditional variance into a matrix expression, but the derivation must preserve the dependence structure of all mmm signals and the special scalar coordinate of yyy. The boundary ∣NI∣=m|NI|=m∣NI∣=m makes yyy redundant and its covariance singular, so the inverse formula requires the paper's standing condition that both investor types are present.

The rate claim requires more than the sign of the first derivative. The printed second-derivative argument on p. 6227 omits the minus sign in the derivative of a matrix inverse; the nonnegativity conclusion survives, but its formal statement records the corrected derivative value. The strict increasing-rate clause in the goal is stronger than the non-strict inequality displayed in that proof. These distinctions must be established for every portfolio outside the market span, including edge dimensions, rather than inferred from a numerical example.

Formalization scope

Assets are indexed by Fin n and investors by Fin m, both starting at zero. The final coordinate of yyy is represented by the Unit side of Fin n ⊕ Unit. Mathlib's multivariate Gaussian law lives on a Euclidean space; a SignalModel bundles the Gaussian laws, positive definiteness, mutual independence, and measurability of payoffs and noises. Joint normality follows from these model assumptions. The measurability fields ensure that σ(y)\sigma(y)σ(y) is a sub-σ-algebra of the ambient one.

The conditional variance in the goal is Mathlib's conditional variance of x′vx'vx′v given σ(y)\sigma(y)σ(y), compared almost surely across choices of NININI. It is not defined by the Schur-complement formula: milestone (20) asserts that identity. The matrix Σyy(N)\Sigma_{yy}(N)Σyy​(N) and the coefficients in (19) use a real variable N∈(0,m)N\in(0,m)N∈(0,m) in the derivative milestones, extending the integer count ∣NI∣|NI|∣NI∣ used by the economy. Positive definiteness and 1≤∣NI∣<m1\le |NI|<m1≤∣NI∣<m rule out the junk inverse and zero-denominator cases. The strict discrete-increment statement expresses “increasing rate” in the goal.

The equilibrium prices and their equivalence with yyy in (16), Theorems 1–2, and the later comovement and CAPM results are outside this mission. Contributions are welcome on Gaussian conditioning, covariance identities, matrix inverse differentiation, and the comparison of successive portfolio variances. General Gaussian and matrix lemmas can be reused beyond this paper.

Selected references

  • Shmuel Baruch and Xiaodi Zhang, The Distortion in Prices Due to Passive Investing, Management Science 68(8), 6219–6234, 2022. doi:10.1287/mnsc.2021.4114.
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🏆Completed
Differential GeometryGeneral RelativityMathematical Physics·Captain: He Wang

Exact Vacuum Atlas III: Matrix Integrating Factors and Local Equivalence of Kerr–Newman Perturbation SystemsResearch Paper

Motivation

Linear perturbations of a rotating, charged black hole are governed, after a mode decomposition, by a coupled first-order system for the linearised Weyl and Maxwell quantities. For the uncharged Kerr solution these equations decouple into the Teukolsky equation, and mode stability was proved by Whiting (1989) through an integral transform. For the charged Kerr–Newman family the Weyl and Maxwell perturbations stay coupled, and no separation of variables was available for decades; Giorgi (2020, arXiv:2002.07228) obtained coupled Teukolsky-type and Regge–Wheeler-type systems but not a separated form. Hintz (2026, arXiv:2609.33661) found a matrix integrating factor that removes the same-chirality coefficient A from the first-order derivatives and makes the remaining coefficient matrix split into a radial and an angular part; from this he derives separation of variables and mode stability for subextremal Kerr–Newman black holes. The algebraic core of that derivation is a chain of explicit, local, coordinate-level transformations between first-order systems on the exterior region. This mission formalises that chain.

Prior formalised material on this platform: the Boyer–Lindquist Kerr vacuum certificate and the Exact Vacuum Atlas I/II coordinate certificates and transports (same author, same environment). None of them touch perturbation theory; this mission starts a new, independent layer and does not depend on them.

Setting

Fix subextremal Kerr–Newman parameters M>0M>0M>0, a∈Ra\in\mathbb Ra∈R, Q≠0Q\neq 0Q=0 with a2+Q2<M2a^2+Q^2<M^2a2+Q2<M2 (Lean: Hintz2026.SubextremalKN). Put Δ(r)=r2−2Mr+a2+Q2\Delta(r)=r^2-2Mr+a^2+Q^2Δ(r)=r2−2Mr+a2+Q2, r+=M+M2−a2−Q2r_+=M+\sqrt{M^2-a^2-Q^2}r+​=M+M2−a2−Q2​, and work on the open set

U={(r,θ)∈R2: r>r+, 0<θ<π}U=\{(r,\theta)\in\mathbb R^2:\ r>r_+,\ 0<\theta<\pi\}U={(r,θ)∈R2: r>r+​, 0<θ<π}

(Lean: U p, with x 0 = r, x 1 = θ). Write ρˉ=r+iacos⁡θ\bar\rho=r+ia\cos\thetaρˉ​=r+iacosθ, ρˉ∗=r−iacos⁡θ\bar\rho^*=r-ia\cos\thetaρˉ​∗=r−iacosθ. Fix a frequency ω∈R\omega\in\mathbb Rω∈R and an azimuthal number mmm (kept real in Lean; integrality is not used by any statement here), and put K=−(r2+a2)ω+amK=-(r^2+a^2)\omega+amK=−(r2+a2)ω+am, Q^=−aωsin⁡θ+m/sin⁡θ\hat Q=-a\omega\sin\theta+m/\sin\thetaQ^​=−aωsinθ+m/sinθ.

The first-order operators of the Newman–Penrose formalism in these coordinates are, for a label jjj,

Dj=∂r+iKΔ+jΔ′Δ,Lj=∂θ+Q^+jcot⁡θ,\mathcal D_j=\partial_r+\tfrac{iK}{\Delta}+j\tfrac{\Delta'}{\Delta},\qquad \mathcal L_j=\partial_\theta+\hat Q+j\cot\theta,Dj​=∂r​+ΔiK​+jΔΔ′​,Lj​=∂θ​+Q^​+jcotθ,

with daggers Dj†,Lj†\mathcal D_j^\dagger,\mathcal L_j^\daggerDj†​,Lj†​ obtained by K↦−KK\mapsto -KK↦−K, Q^↦−Q^\hat Q\mapsto-\hat QQ^​↦−Q^​. Partial derivatives are coordinate-slice derivatives (Lean: cpd), and all fields are complex-valued functions on R2\mathbb R^2R2 that are C∞C^\inftyC∞ on UUU.

System (1) (positive spin) is the system (1a)–(1d) of Hintz for the four rescaled mode quantities (ψ2,ψ1,k,s)(\psi_2,\psi_1,k,s)(ψ2​,ψ1​,k,s); the negative-spin system is obtained from it by the replacement rules stated in the paper (Lean: res1a–res1d, res1aN–res1dN, each the difference "left side minus right side"). The chiral variables (3) are

y±(+)=Δ5/4sin⁡θ(ψ2±iΔ−1/2ψ1−2Q(k±iΔ−1/2s)),y±(−)=Δ−3/4sin⁡θ(ψ−2∓iΔ1/2ψ−12Q(n∓iΔ1/2ℓ)).y_\pm^{(+)}=\Delta^{5/4}\sqrt{\sin\theta}\begin{pmatrix}\psi_2\pm i\Delta^{-1/2}\psi_1\\ -2Q(k\pm i\Delta^{-1/2}s)\end{pmatrix},\qquad y_\pm^{(-)}=\Delta^{-3/4}\sqrt{\sin\theta}\begin{pmatrix}\psi_{-2}\mp i\Delta^{1/2}\psi_{-1}\\ 2Q(n\mp i\Delta^{1/2}\ell)\end{pmatrix}.y±(+)​=Δ5/4sinθ​(ψ2​±iΔ−1/2ψ1​−2Q(k±iΔ−1/2s)​),y±(−)​=Δ−3/4sinθ​(ψ−2​∓iΔ1/2ψ−1​2Q(n∓iΔ1/2ℓ)​).

System (4) is (Δ ∂r∓i∂θ∓A)y±=(c(ς)I∓B(ς))y∓(\sqrt\Delta\,\partial_r\mp i\partial_\theta\mp A)y_\pm=(c^{(\varsigma)}I\mp B^{(\varsigma)})y_\mp(Δ​∂r​∓i∂θ​∓A)y±​=(c(ς)I∓B(ς))y∓​ with the explicit 2×22\times22×2 matrices AAA, B(ς)B^{(\varsigma)}B(ς) and scalar c(ς)c^{(\varsigma)}c(ς) of the paper (Lean: A, Bmat, cscalar; ς=±1\varsigma=\pm1ς=±1 is the spin label). The integrating factor is the matrix X(r,θ)X(r,\theta)X(r,θ) of equation (5), with det⁡X=Q2−M2\det X=Q^2-M^2detX=Q2−M2, and system (7) is

(Δ ∂r−i∂θ)z+=C z−,(Δ ∂r+i∂θ)z−=adj⁡(C) z+,(\sqrt\Delta\,\partial_r-i\partial_\theta)z_+=C\,z_-,\qquad(\sqrt\Delta\,\partial_r+i\partial_\theta)z_-=\operatorname{adj}(C)\,z_+,(Δ​∂r​−i∂θ​)z+​=Cz−​,(Δ​∂r​+i∂θ​)z−​=adj(C)z+​,

for z+=adj⁡(X)y+z_+=\operatorname{adj}(X)y_+z+​=adj(X)y+​, z−=X∗y−z_-=X^*y_-z−​=X∗y−​ and C=det⁡X⋅X−1(cI−B)(X∗)−1C=\det X\cdot X^{-1}(cI-B)(X^*)^{-1}C=detX⋅X−1(cI−B)(X∗)−1. The paper's separation statement is that C=R(r)+iΘ(θ)C=R(r)+i\Theta(\theta)C=R(r)+iΘ(θ) with four explicit coefficient functions R0,R1,Θ0,Θ1R_0,R_1,\Theta_0,\Theta_1R0​,R1​,Θ0​,Θ1​.

Formalization targets

Goal — local equivalence of the original and the transformed systems

for all C∞ fields and all x∈U:(1) holds at x  ⟺  (7) holds at x for (z+,z−)=T(ψ),\text{for all }C^\infty\text{ fields and all }x\in U:\qquad \text{(1) holds at }x\iff\text{(7) holds at }x\text{ for }(z_+,z_-)=T(\psi),for all C∞ fields and all x∈U:(1) holds at x⟺(7) holds at x for (z+​,z−​)=T(ψ),

for both spins (Lean: Hintz2026.main_pos, Hintz2026.main_neg, with the on-UUU forms main_pos_on_U, main_neg_on_U). The composite transformation is explicitly invertible on UUU: first recover y+=(Q2−M2)−1Xz+y_+=(Q^2-M^2)^{-1}Xz_+y+​=(Q2−M2)−1Xz+​ and y−=(X∗)−1z−y_-=(X^*)^{-1}z_-y−​=(X∗)−1z−​, then apply the inverse chiral map invPos or invNeg. The goal leaves the frequency and azimuthal parameters free, assumes nothing beyond subextremality and C∞C^\inftyC∞ regularity on UUU, and does not assert anything at the horizon or at infinity.

Milestones

  1. The matrix integrating factor: (Δ∂r−i∂θ)X=AX(\sqrt\Delta\partial_r-i\partial_\theta)X=AX(Δ​∂r​−i∂θ​)X=AX and the companion equation for (X∗)−1(X^*)^{-1}(X∗)−1 (Dminus_X_eq_AX, Dplus_XstarInv_eq).
  2. Residual identities and solution correspondence for the integrating factor (Dm_Xv_sub_AXv, Dp_Yv_add_AYv, Dm_zero_iff_Xv_residual_zero_on_U, …).
  3. The coefficient separation C=R(r)+iΘ(θ)C=R(r)+i\Theta(\theta)C=R(r)+iΘ(θ) verified entrywise against the paper's four coefficients (Cmat_eq_Csep), and adj⁡C=RT−iΘ\operatorname{adj}C=R^{\mathsf T}-i\ThetaadjC=RT−iΘ.
  4. Local equivalence (4) ⟺ (7) for arbitrary C∞C^\inftyC∞ fields (system4_iff_system7).
  5. The eight chiralisation identities expressing the residuals of (4) for the chiral variables as an explicit invertible combination of the residuals of (1), for both spins (ident_*, identN_*), and the equivalence (1) ⟺ (4) (sys1_iff_sys4_pos, sys1_iff_sys4_neg).

Significance

The chain (1)→(4)→(7) is the step on which the rest of Hintz's argument rests: once CCC is known to separate, the angular operator can be diagonalised and the radial problem reduces to a scalar second-order equation, which is where the mode-stability argument lives. The transformations are algebraic but far from trivial to check by hand — each entry of CCC is a rational-trigonometric expression in rrr, θ\thetaθ, ω\omegaω, mmm and the three parameters, and the cancellation of all mixed (r,θ)(r,\theta)(r,θ) terms is the content of the separation claim.

Everything in this mission is already proved in the paper. What the mission adds is a machine-checked verification of the explicit coefficient data and of the transformation identities for arbitrary C∞C^\inftyC∞ fields, with the regularity and domain hypotheses made explicit. All targets listed here already carry accepted proofs on this platform; the mission records them as a public, reviewable dependency tree. Not formalised here: the derivation of (1) from the Einstein–Maxwell equations, the angular eigenvalue problem, the radial reduction, the Whiting-type transform, and mode stability itself.

Difficulty

The naive approach — substituting the chiral variables into (4) and comparing with (1) term by term — produces hundreds of rational terms with half-integer powers of Δ\DeltaΔ and of sin⁡θ\sin\thetasinθ. The first-order terms match by construction; the difficulty is that the zeroth-order terms only match after using Δ 2=Δ\sqrt\Delta^{\,2}=\DeltaΔ​2=Δ, cos⁡2θ=1−sin⁡2θ\cos^2\theta=1-\sin^2\thetacos2θ=1−sin2θ and the specific values of AAA, BBB, ccc. A second trap is in the negative-spin system: the replacement rules put sign changes inside the operators, and an identity proved for a "simplified" version of the rules would be an identity about a different system. The formalisation keeps the rules literally and derives linearity separately.

Formalization scope

Coordinates are R2\mathbb R^2R2 with x 0=rx\,0=rx0=r, x 1=θx\,1=\thetax1=θ; no manifold, tetrad or spacetime object is defined. Derivatives are coordinate-slice derivatives (deriv along one coordinate), and the final unknown-field interfaces use ContDiffOn ℝ ∞ _ (U p); auxiliary statements may require only coordinate-slice differentiability, and explicit coefficient statements retain the stronger analytic order ω. Real exponents Δ5/4\Delta^{5/4}Δ5/4, Δ−3/4\Delta^{-3/4}Δ−3/4 are Real.rpow;  \sqrt{\ } ​ is Real.sqrt. All coefficient matrices are explicit Matrix (Fin 2) (Fin 2) ℂ; the separated form R+iΘR+i\ThetaR+iΘ is an independent explicit definition, not derived from CCC, so Cmat_eq_Csep is a genuine check. The spin label is a real parameter ς\varsigmaς in the definitions of BBB and ccc; the two spins are the instances ς=±1\varsigma=\pm1ς=±1, each proved separately with its own chiral variables.

Nothing here is vacuous: the systems are Props about arbitrary fields, the residuals are explicit, and the domain UUU is nonempty and open. A reader can check that the Lean definitions reproduce the paper's formulas from the transcript of the paper's equations included with the source.

Reusable beyond this mission: the slice-derivative calculus (cpd, Dm, Dp, product and sum rules), the integrating-factor layer (X, A, invertibility, residual identities) and the prefactor calculus for Δqsin⁡θ\Delta^{q}\sqrt{\sin\theta}Δqsinθ​.

Selected references

  • P. Hintz, Perturbations of Kerr–Newman black holes: separation and mode stability, arXiv:2609.33661 (2026). https://arxiv.org/abs/2609.33661
  • E. Giorgi, Electromagnetic-gravitational perturbations of Kerr–Newman spacetime: the Teukolsky and Regge–Wheeler equations, arXiv:2002.07228 (2020). https://arxiv.org/abs/2002.07228
  • B. F. Whiting, Mode stability of the Kerr black hole, J. Math. Phys. 30 (1989) 1301–1305. https://doi.org/10.1063/1.528308
  • T. Adamo, E. T. Newman, The Kerr–Newman metric: a review, Scholarpedia 9 (2014), arXiv:1410.6626. https://arxiv.org/abs/1410.6626
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Machine LearningProbabilityStochastic Systems·Captain: mikedeng1

Mean Field Analysis of Deep Neural Networks: The SGD-Trained Two-Hidden-Layer Network Converges, as Its Layer Widths Grow in Turn, to the Unique Solution of a Limiting Integro-Differential SystemResearch Paper

Motivation

A neural network can change its behavior substantially when both its width and its training duration grow. For a network with two hidden layers, the parameters of the layers interact during training, so a large-width description must account for the output of the actual optimization algorithm. Sirignano and Spiliopoulos study this question for online stochastic gradient descent (SGD) under a mean-field normalization. Their Theorem 2.3 identifies the limit of the trained network when the first hidden layer grows, followed by the second, and gives a rate for the intermediate second-layer approximation. The result concerns a trained network: all three families of weights evolve at every SGD step.

The normalization matters. Each hidden layer contributes an average, with factors 1/N11/N_11/N1​ and 1/N21/N_21/N2​ for the first and second widths. The learning rates depend on those widths, so the output can continue changing on the time scale of N1N_1N1​ SGD steps. The paper notes that a different scaling may lead to a different limiting equation or to no nontrivial training behavior at large width. A precise statement therefore needs the finite network and its SGD updates alongside the limiting equations, not merely a claim about an abstract mean-field flow.

Setting

Let ddd be an input dimension and x∈Rdx\in\mathbb R^dx∈Rd an input. A two-hidden-layer network has N1N_1N1​ first-layer units and N2N_2N2​ second-layer units. Its parameters are output weights CiC^iCi, first-layer vectors W1,jW^{1,j}W1,j, and second-layer weights W2,i,jW^{2,i,j}W2,i,j. With an activation σ:R→R\sigma:\mathbb R\to\mathbb Rσ:R→R, its output is

gθN1,N2(x)=1N2∑i=1N2Ciσ(1N1∑j=1N1W2,i,jσ(W1,j⋅x)).g_\theta^{N_1,N_2}(x)=\frac1{N_2}\sum_{i=1}^{N_2}C^i\sigma\left(\frac1{N_1}\sum_{j=1}^{N_1}W^{2,i,j}\sigma(W^{1,j}\cdot x)\right).gθN1​,N2​​(x)=N2​1​i=1∑N2​​Ciσ(N1​1​j=1∑N1​​W2,i,jσ(W1,j⋅x)).

Training samples (xk,yk)(x_k,y_k)(xk​,yk​) are independent draws from a probability law π\piπ supported on a compact product X×YX\times YX×Y. The three initial weight families are mutually independent and identically distributed within each family, with laws μc\mu_cμc​, μW1\mu_{W^1}μW1​, and μW2\mu_{W^2}μW2​. Each law has a continuous density and compact support. The activation is twice continuously differentiable and, as the paper's Cb2C_b^2Cb2​ notation requires, it and its first two derivatives are bounded. These are the standing conditions of Assumption 2.1.

At each step, SGD updates all parameters from the same previous parameter state and the same sample. The learning rates in equation (2.1) are αC=N2/N1\alpha_C=N_2/N_1αC​=N2​/N1​, αW,1=1\alpha_{W,1}=1αW,1​=1, and αW,2=N2\alpha_{W,2}=N_2αW,2​=N2​, applied with the step-size denominators in equation (1.4). The output at time ttt is the output after ⌊N1t⌋\lfloor N_1t\rfloor⌊N1​t⌋ updates. For fixed N2N_2N2​, the first-width limit is described by an N2N_2N2​-particle system. Its first-layer particle retains both its initial first-layer vector and the full vector of its N2N_2N2​ second-layer initial weights, because its dynamics depend on all of them. The second-width limit is a limiting integro-differential system for representative paths C~tc\widetilde C_t^cCtc​, W~t1,w\widetilde W_t^{1,w}Wt1,w​, and W~t2,c,w,u\widetilde W_t^{2,c,w,u}Wt2,c,w,u​.

Formalization targets

The main limit

For t∈[0,1]t\in[0,1]t∈[0,1] and x∈Xx\in Xx∈X, the target is the existence and uniqueness of the limiting system (2.6), together with

lim⁡N2→∞lim⁡N1→∞gtN1,N2(x)=gt(x)in probability,gt(x)=∫C~tc σ(Z~tc(x)) μc(dc).\lim_{N_2\to\infty}\lim_{N_1\to\infty}g_t^{N_1,N_2}(x)=g_t(x) \quad\text{in probability}, \qquad g_t(x)=\int \widetilde C_t^c\,\sigma(\widetilde Z_t^c(x))\,\mu_c(dc).N2​→∞lim​N1​→∞lim​gtN1​,N2​​(x)=gt​(x)in probability,gt​(x)=∫Ctc​σ(Ztc​(x))μc​(dc).

The order is fixed: N1N_1N1​ grows first while N2N_2N2​ is held fixed. The goal states the entire Theorem 2.3, including the existence clause; without existence, convergence quantified only over solutions would have no content.

Quantitative intermediate limit

For the particle output gtN2g_t^{N_2}gtN2​​, the same theorem gives a constant K<∞K<\inftyK<∞ such that

sup⁡x∈XE[∣gtN2(x)−gt(x)∣]≤KN2.\sup_{x\in X}\mathbb E\bigl[|g_t^{N_2}(x)-g_t(x)|\bigr] \le \frac K{\sqrt{N_2}}.x∈Xsup​E[∣gtN2​​(x)−gt​(x)∣]≤N2​​K​.

The attack path records the finite-particle well-posedness of Lemma A.5; the first-width output limit stated after Lemma 2.2; the uniform particle bound (5.5); the sampling-variance estimate (5.9); the mean squared particle-error estimate (5.15); the output rate from Section 5.8; and uniqueness from Lemma 6.1. Each is a stated result or displayed assertion in the source. The rate and uniqueness milestones are also conclusions of the goal theorem.

Significance

The theorem specifies what the output of this trained network approaches, rather than only describing the parameters of a network at initialization. It connects the discrete SGD recursion to a finite particle system and then to a deterministic output from a limiting system. The N2−1/2N_2^{-1/2}N2−1/2​ bound makes the second-width approximation quantitative, while uniqueness makes the limiting output independent of the choice of representative solution. These claims provide the basis for the paper's later discussion of global convergence under stronger assumptions; they do not themselves assert that training reaches a global minimum.

The paper proves the first-width and error estimates and gives a uniqueness argument for the limiting system. It asserts existence of a solution to (2.6) in Theorem 2.3, although a separate existence proof is not supplied there. A complete machine-checked development must account for that clause as well as the known arguments. No proof of this mission's goal or milestones is currently included in the draft Lean statements; they are targets for solvers. The network model, initialization law, and particle equations can also serve as reusable interfaces for further formal work on trained wide networks.

Difficulty

A direct large-width argument cannot treat the two widths as one undifferentiated limit. With N2N_2N2​ fixed, the shared first-layer weights couple all second-layer units. The first limit is a stochastic statement about the SGD iterates and a particle system whose state includes a vector of initial second-layer weights. Only after that limit can the N2N_2N2​ fluctuations be controlled. The second stage must bound both the sampling fluctuation of the representative output and the discrepancy between the particle paths and the limiting paths. The source's existence assertion also needs a mathematical justification in the specified continuous-solution class. Simply taking a pointwise limit of the network formula leaves all of these issues unresolved.

Formalization scope

Lean uses EuclideanSpace ℝ (Fin d) for inputs, Fin N_1 and Fin N_2 for neuron indices, and Measure.pi or Measure.infinitePi for independent initial weights and data. The arrays of all widths live on one probability space with the stated product law. The SGD recursion is the simultaneous update (1.4), with the exact factors from (2.1), and time uses ⌊N1t⌋\lfloor N_1t\rfloor⌊N1​t⌋. The representative and particle systems are written in integral form. Solutions are jointly continuous on [0,1][0,1][0,1] times the compact supports of their initial states; this supplies the regularity needed for the integrals and matches the class used in Lemma 6.1. No nonempty-input-set assumption or monotonicity assumption on σ\sigmaσ is added.

The inner probability limit in the goal uses a limsup in N1N_1N1​. Footnote 2 writes an inner limit but does not assert its existence at every probability threshold; the limsup version implies its claim whenever that inner limit exists. A single rate constant works for all t∈[0,1]t\in[0,1]t∈[0,1], all positive N2N_2N2​, and all x∈Xx\in Xx∈X. The particle state includes the full vector of initial W2W^2W2 values, and the conditional expectation defining its second-layer preactivation is an integral over their product law at fixed initial CCC values. The finite network, particle system, and limiting system must be connected by the stated results; an arbitrary output function with the desired limit would not formalize this theorem.

A complete development needs probability measures on product spaces, integrals of continuous functions on compact supports, convergence in measure, finite-sample variance estimates, and existence and uniqueness theory for the coupled integral systems. Contributions to these pieces and to the stated milestone theorems are within scope. The measure-valued Skorokhod-space statement of Lemma 2.2, numerical experiments, and the paper's separate global-convergence theorem are outside this mission.

Selected references

  • Justin Sirignano and Konstantinos Spiliopoulos, Mean Field Analysis of Deep Neural Networks, Mathematics of Operations Research, 2022; arXiv:1903.04440v5 preprint, 2021. This mission uses the preprint's page and equation numbering.
9 thms1 active userReviewed
Quantum Information·Captain: Goku

A memory and gate efficient algorithm for unitary mixed Schur samplingResearch Paper

Motivation

We formalize the task of unitary Schur sampling -- an extension of weak Schur sampling -- which is the process of measuring the Young label and the unitary group register of an input mmm qudit state. Intuitively, this task is equivalent to applying the Schur transform, projecting onto the isotypic subspaces of the unitary and symmetric groups indexed by the Young labels, and discarding of the permutation register. As such unitary Schur sampling is the natural task in processes such as quantum state tomography or spectrum estimation. We generalize this task to unitary mixed Schur sampling to account for the recently introduced mixed Schur-Weyl transform. We provide a streaming algorithm which achieves an exponential reduction in the memory complexity and a polynomial reduction in the gate complexity over na"ive algorithms for the task of unitary (mixed) Schur sampling. Further, we show that if the input state has limited rank, the gate and memory complexities of our streaming algorithm as well as the algorithms for the full Schur and mixed Schur transforms are further reduced. Our work generalizes and improves on the results in arXiv2309.11947.

This mission is the statement-level formalization of A memory and gate efficient algorithm for unitary mixed Schur sampling (arXiv:2410.15793v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

2 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Four properties of homogeneous Littlewood–Richardson coefficients (Lemma 11, PDF p. 32). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

12 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 1: A source-pinned approximation metric, exact synthesis exponent, and multivariate asymptotic convention. (source-ambiguity)
  • Corollary 2: A source-pinned approximation metric, exact synthesis exponent, and multivariate asymptotic convention. (source-ambiguity)
  • Lemma 8: A source-pinned approximation metric, exact synthesis exponent, and multivariate asymptotic convention. (source-ambiguity)
  • Lemma 9: A source-pinned approximation metric, exact synthesis exponent, and multivariate asymptotic convention. (source-ambiguity)
  • Remarks 1 and 4: A source-pinned approximation metric, exact synthesis exponent, and multivariate asymptotic convention. (source-ambiguity)
  • Appendix B2, (B6)–(B9): A consistent total-memory bound and a classical bit-precision/gate model. (source-ambiguity)
  • Appendix B3, (B20)–(B24): A consistent distinction between per-CG and streaming gate costs, and between state and total storage. (source-ambiguity)
  • Appendix B3, (B13)–(B19): Consistent valid-support indexing at every recursion depth. (source-ambiguity)
  • Lemma 5, (54)–(55): Constructed GT-basis CG/dual-CG maps and compatible path co-restrictions in both signs. (hard)
  • Lemma 7, (59)–(60): An actual sequential path instrument, with fixed mixed Schur coordinates, final-label marginal, and conditional retained irrep state. (hard)
  • Lemma 12, (C8)–(C9): Concrete rational staircase representations and the conjugate-tensor representation equivalence with canonical multiplicities. (hard)
  • Lemma 14, (C21): A concrete mixed isotypic decomposition or exact mixed sector projector tied to U tensor-power m times conjugate U tensor-power n. (hard)

Selected references

  • A memory and gate efficient algorithm for unitary mixed Schur sampling, arXiv:2410.15793v2, https://arxiv.org/abs/2410.15793v2
5 thms1 active userReviewed
Quantum Information·Captain: Goku

Distillation of secret key and entanglement from quantum statesResearch Paper

Motivation

We study and solve the problem of distilling secret key from quantum states representing correlation between two parties (Alice and Bob) and an eavesdropper (Eve) via one-way public discussion: we prove a coding theorem to achieve the "wire-tapper" bound, the difference of the mutual information Alice-Bob and that of Alice-Eve, for so-called cqq-correlations, via one-way public communication. This result yields information--theoretic formulas for the distillable secret key, giving ``ultimate'' key rate bounds if Eve is assumed to possess a purification of Alice and Bob's joint state. Specialising our protocol somewhat and making it coherent leads us to a protocol of entanglement distillation via one-way LOCC (local operations and classical communication) which is asymptotically optimal: in fact we prove the so-called "hashing inequality" which says that the coherent information (i.e., the negative conditional von Neumann entropy) is an achievable EPR rate. This result is well--known to imply a whole set of distillation and capacity formulas which we briefly review.

This mission is the statement-level formalization of Distillation of secret key and entanglement from quantum states (arXiv:quant-ph/0306078v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

11 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Theorem 1: one-way secret-key coding theorem (Theorem 1, PDF p. 2). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Selected references

  • Distillation of secret key and entanglement from quantum states, arXiv:quant-ph/0306078v1, https://arxiv.org/abs/quant-ph/0306078v1
21 thms1 active userReviewed
Quantum Information·Captain: Goku

Bath dimension and initial entropy for closed repeated use of a quantum channelResearch Paper

Motivation

We characterize the bath resources needed to supply repeated uses of a fixed finite-dimensional quantum channel in a closed device. For each horizon TTT, one bath, one initial state and one repeated unitary are fixed before the user. Each output is returned before the next input arrives; no reset, discard, fresh ancilla or uncounted controller is available. Approximation error must vanish against arbitrary adaptive users with quantum memory and references. Writing r=lim⁡log⁡2(RT)/Tr=\lim \log_2(R_T)/Tr=limlog2​(RT​)/T for the bath dimension rate and s=lim⁡S(ωT)/Ts=\lim S(ω_T)/Ts=limS(ωT​)/T for the actual initial entropy rate, we prove that the achievable region is exactly s≥0s\ge 0s≥0, r+s≥hr+s\ge hr+s≥h and r−s≥κr-s\geκr−s≥κ. Here hhh is maximum entropy exchange and κκκ is a smoothed independent-reference extension cost, with the zero-error limit taken before the supremum over full-rank inputs. Its exact fixed-input form is an affine transform of the zero-leakage quantum privacy funnel. The minimum dimension rate is (h+κ)/2(h+κ)/2(h+κ)/2. The proof combines entropy converses, a bath-dimension-independent support repair, and a closed adaptive implementation of encoder-only fully quantum Slepian--Wolf recycling. All seeds, clocks, workspace and retained residues are counted. Worked examples include dephasing, pure replacement and a qubit channel with 0<κ<h0<κ<h0<κ<h. No computability of κκκ or efficient circuit synthesis is claimed. △ Less

This mission is the statement-level formalization of Bath dimension and initial entropy for closed repeated use of a quantum channel (arXiv:2609.18267v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

9 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Theorem 3.1: uniform collision gain (Theorem 3.1, PDF p. 6). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

13 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 2.1 (seed paper result): exact bath-dimension/initial-entropy rate region: Closed all-horizon causal device and complete adaptive process metric, actual rate-limit region, counted padding/internal-purification transformations (hard)
  • Theorem 2.2: same-spectrum converse: Same actual initializer in two complete adaptive tester experiments and all-integer liminf resource rates (hard)
  • Theorem 5.1: causal balancing for any fixed finite exact witness: Causal block compiler with actual flat initializer, repeated-unitary semantics and separately converging seed/data rates (hard)
  • Proposition 7.1: unitary channels: Complete all-horizon memory rate c_seq and bath-free repeated-unitary realization (hard)
  • Proposition 7.2: qubit dephasing and exact streaming corner: Counted exact streaming process from independent Pauli generators, ordered history words and one clocked unitary (hard)
  • Proposition 7.3: pure replacement: Pure-replacer complete operating memory rate and counted preallocated-cell/clock process (hard)
  • Proposition 8.1: shared-seed marginal/complete separation: Shared-bit repeated controlled-Z process, product-marginal repeatability and supremum complete adaptive error (hard)
  • Section 8, unnumbered: zero memory rate iff unitary: Zero complete operating memory rate as an asymptotic repeated-service property (hard)
  • Lemma A.1: fixed adaptive spectral concentration projector: Reachable states of adaptive controllers with fresh comparison channels and untouched spent Lambda outputs (hard)
  • Lemma A.2: simultaneous bath/exterior/source support and spectral-cap cuts: Exact comparison block and pure complete exterior, including future-accessed spectators and their purifiers (hard)
  • Lemma A.4: exact integer wires and reversible flat-stock preparation: Reversible flat-stock preparation and permanent wire/tranche allocation with immediate collision service (hard)
  • Proposition A.5: joint recycling, every prefix, and one repeated unitary: Joint comparison boundary invariant, actual block composition, every prefix and counted repeated-unitary clock (hard)
  • Proposition A.6: exact actual spectrum and every-horizon limits: Every-integer-horizon compiled family with actual flat spectrum, exact physical counts and separate seed/data limits (hard)

Selected references

  • Bath dimension and initial entropy for closed repeated use of a quantum channel, arXiv:2609.18267v1, https://arxiv.org/abs/2609.18267v1
15 thms1 active userReviewed
Quantum Information·Captain: Goku

Entanglement-assisted capacity of constrained quantum channelResearch Paper

Motivation

In this paper we fill the gap in previous works by proving the formula for entanglement-assisted capacity of quantum channel with additive constraint (such as bosonic Gaussian channel). The main tools are the coding theorem for classical-quantum constrained channels and a finite dimensional approximation of the input density operators for entanglement-assisted capacity. The new version contains improved formulation of sufficient conditions under which suprema in the capacity formulas are attained.

This mission is the statement-level formalization of Entanglement-assisted capacity of constrained quantum channel (arXiv:quant-ph/0211170v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

1 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Trace-norm compactness of an energy sublevel (§3, unnumbered Lemma (proof on PDF p.11), PDF p. 10). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

9 results of the paper are not stated yet, because the library lacks an interface they need:

  • §1, Proposition 1: An operational constrained c-q coding model on arbitrary input alphabets and general trace-class output states, with genuine product outputs, bounded POVMs, maximal message error, and a liminf achievable-rate capacity. (hard)
  • §1, Proposition 2 (conclusion on p.3): Borel-probability barycenters and integrated entropy for trace-norm state-valued maps, coupled to a genuine bounded-below unbounded selfadjoint observable with Gibbs trace. (hard)
  • §2, Proposition 3, (19)--(20): Parallel general trace-class CPTP channel powers, constrained block codes and two separately defined information optimizations with different feasible sets. (hard)
  • §3, Proposition 4, (30): Energy-constrained operational entanglement-assisted block capacity on arbitrary Hilbert spaces, plus actual purification/reference extension and the finite-entropy mutual-information interface. (hard)
  • §3, (31)--(32): The special locally encoded common-resource assisted ensemble class and its block Holevo optimum, distinct from operational assisted codes. (hard)
  • §3, assertion before (33): Constrained channel mutual information for arbitrary entangled block states, with actual reference purifications and additive energy expectation. (hard)
  • §3, finite-rank approximation and (35) on p.10: Constructed positive-eigenvalue spectral truncations, their normalized purifications, and channel mutual information in one compatible operator model. (hard)
  • §3, Proposition 5, (37): Actual dual-channel domination for bounded-below unbounded output observables, Gibbs trace, and an operational assisted capacity attaining state. (hard)
  • Closing paragraph; (30) with (36): Extended-valued relative-entropy channel mutual information coupled to operational assisted capacity without either entropy restriction. (hard)

Selected references

  • Entanglement-assisted capacity of constrained quantum channel, arXiv:quant-ph/0211170v2, https://arxiv.org/abs/quant-ph/0211170v2
3 thms1 active userReviewed
Quantum Information·Captain: Goku

The mixed Schur transform: efficient quantum circuit and applicationsResearch Paper

Motivation

The Schur transform, which block-diagonalizes the tensor representation U⊗nU^{\otimes n}U⊗n of the unitary group Ud\mathbf{U}_dUd​ on nnn qudits, is an important primitive in quantum information and theoretical physics. We give a generalization of its quantum circuit implementation due to Bacon, Chuang, and Harrow (SODA 2007) to the case of mixed tensor U⊗n⊗Uˉ⊗mU^{\otimes n} \otimes \bar{U}^{\otimes m}U⊗n⊗Uˉ⊗m, where Uˉ\bar{U}Uˉ is the dual representation. This representation is the symmetry of unitary-equivariant channels, which find various applications in quantum majority vote, multiport-based teleportation, asymmetric state cloning, black-box unitary transformations, etc. The "mixed" Schur transform contains several natural extensions of the representation theory used in the Schur transform, in which the main ingredient is a duality between the mixed tensor representations and the walled Brauer algebra. Another element is an efficient implementation of a "dual" Clebsch-Gordan transform for Uˉ\bar{U}Uˉ. The overall circuit has complexity O~((n+m)d4)\widetilde{O} ((n+m)d^4)O((n+m)d4). Finally, we show how the mixed Schur transform enables efficient implementation of unitary-equivariant channels in various settings and discuss other potential applications, including an extension of permutational quantum computing that includes partial transposes.

This mission is the statement-level formalization of The mixed Schur transform: efficient quantum circuit and applications (arXiv:2310.01613v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

2 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Two-input conclusive teleportation: exact success and corrected output (Section 5.1.1: two-input conclusive teleportation success, PDF p. 29). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

18 results of the paper are not stated yet, because the library lacks an interface they need:

  • Main result / Corollary 4.12: efficient mixed Schur isometry: Concrete signed-staircase rational irreps with orthonormal GT and dimension-truncated path coordinates, their fixed mixed Schur isometry, and its binary channel/resource semantics. (hard)
  • Section 3.3 and Remark 3.1: cascade correctness and factor-order flexibility: Ordinary and dual CG maps on the concrete signed GT sectors, path extension/reindexing and canonical permutations for factor type words. (hard)
  • Theorem 4.5: multiplicity-free dual Wigner–Eckart: Concrete rational-irrep actions in GT bases and the actual multiplicity-free dual CG matrix. (hard)
  • Proposition 4.6: dual CG coefficient tensor operators: The source dual CG coefficient blocks and their concrete irrep actions. (hard)
  • Lemma 4.7: restriction of the coefficient tensor operators: Compatible GT restriction inclusions between U(d) and U(d-1) and actual coefficient tensor blocks. (hard)
  • Proposition 4.8: reduced Wigner coefficient recursion: The constructed restriction blocks and reduced coefficients relative to the lower-dimensional source dual CG transform. (hard)
  • Section 4.3 Eqs.(69)–(71): recursive factorization: The modified lower dual transform and reduced Wigner rotation on valid dependent label sectors. (hard)
  • Remark 4.10: coherent reduced Wigner operator synthesis: A concrete reduced-Wigner target in the source GT conventions and its uniform reversible finite-precision coefficient/synthesis computation. (hard)
  • Corollary 4.11: efficient dual Clebsch–Gordan transform: The actual coherent dual CG transform over bounded staircase labels and its encoded circuit/workspace interface. (hard)
  • Remark 4.13: extensions to elementary and symmetric-power input irreps: Remark 4.13: extensions to elementary and symmetric-power input irreps (source-ambiguity)
  • Proposition 5.2: deterministic one-input teleportation implementation: Proposition 5.2: deterministic one-input teleportation implementation (source-ambiguity)
  • Section 5.1.1: random symmetric unitaries and random equivariant channels: Section 5.1.1: random symmetric unitaries and random equivariant channels (source-ambiguity)
  • Proposition 5.5: Choi-only average-case observable prediction: A Choi-measurement training law, actual learned estimator function and cost-bearing classical learner implementing the HCP adaptation. (hard)
  • Lemma 5.10: Schur-sparse Choi and square-root block encodings: Valid Schur-label encodings of the actual fixed transform and two-sided sparse row/column/value oracle programs with gate/query accounting. (hard)
  • Proposition 5.11: output expectation estimation from a Choi square root: Proposition 5.11: output expectation estimation from a Choi square root (source-ambiguity)
  • Section 5.1.3: combined diagonal/sparse estimation bounds: Section 5.1.3: combined diagonal/sparse estimation bounds (source-ambiguity)
  • Section 5.1.3: composition by square-root Choi block encodings: Section 5.1.3: composition by square-root Choi block encodings (source-ambiguity)
  • Section 5.2: partially transposed permutational quantum computing: Section 5.2: partially transposed permutational quantum computing (source-ambiguity)

Selected references

  • The mixed Schur transform: efficient quantum circuit and applications, arXiv:2310.01613v1, https://arxiv.org/abs/2310.01613v1
8 thms1 active userReviewed
Quantum Information·Captain: Goku

Multiple-Access Bosonic CommunicationsResearch Paper

Motivation

The maximum rates for reliably transmitting classical information over Bosonic multiple-access channels (MACs) are derived when the transmitters are restricted to coherent-state encodings. Inner and outer bounds for the ultimate capacity region of the Bosonic MAC are also presented. It is shown that the sum-rate upper bound is achievable with a coherent-state encoding and that the entire region is asymptotically achievable in the limit of large mean input photon numbers.

This mission is the statement-level formalization of Multiple-Access Bosonic Communications (arXiv:quant-ph/0506171v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

5 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Operational homodyne and heterodyne coherent-state MAC regions (§II.B, (5)–(8): single-mode homodyne/heterodyne capacity regions, PDF p. 2). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

18 results of the paper are not stated yet, because the library lacks an interface they need:

  • §II.B,(9)–(11): Normalized coherent-state Fock ensembles and collective-receiver product-code MAC capacity (hard)
  • §II.B,(12): Additive random-displacement Fock channel and operational product-code capacity (hard)
  • §II.C,(23)–(27): Collective-receiver wideband bosonic coding and Gaussian ensemble entropy (hard)
  • §III.A,(35)–(40),(50)–(58): Physical Gaussian displaced-state mixtures, raw second moments, and infinite-dimensional entropy (hard)
  • §III.A,(48)–(49): Individual Holevo maximization over physical displacement laws (hard)
  • §III.A,(57)–(58): Joint Holevo sum functional for independent physical displacement laws (hard)
  • §III.A,(31)–(34),(59): Operational HSH two-sender capacity with physical Gaussian seed (hard)
  • §III.B,(60)–(65): Fixed-seed Gaussian beam-splitter MAC and photon-budget accounting (hard)
  • §III.B,(66),Fig.5: Operational fixed-seed Gaussian region realizing the explicit strict extension (hard)
  • §IV,Theorem 1,(67)–(74): Anisotropic attenuator, thermal entropy conjecture, squeeze whitening, and ordinary classical capacity (hard)
  • §IV,(75)–(76): Physical displaced squeezed-seed coding and unconditional anisotropic-channel capacity lower bound (hard)
  • §IV,(77): Thermal attenuator capacity and conditional specialization (hard)
  • §IV,(78)–(79): Pure squeezed-environment attenuator capacity and equal-energy thermal comparison (hard)
  • §V,(80) and individual bounds: Ultimate independent-sender bosonic capacity allowing across-use entanglement (hard)
  • §V, coherent-state sum achievement: Physical coherent encoding attaining the ultimate MAC sum capacity (hard)
  • §V, Gaussian sum achievement: Pure one-port Gaussian seed output and above-threshold physical sum code (hard)
  • Appendix,(A.1): Photon-support-constrained operational quantum MAC regions and their closed limit (hard)
  • Abstract; §V,PDF pp.9–10: Unspecified whole-region high-energy convergence notion (source-ambiguity)

Selected references

  • Multiple-Access Bosonic Communications, arXiv:quant-ph/0506171v2, https://arxiv.org/abs/quant-ph/0506171v2
7 thms1 active userReviewed
🏆Completed
Functional Analysis·Captain: scanstone

Plasticity: the unit balls of c0c_0c0​ sums of real planesResearch Paper

Motivation

A metric space is plastic if every nonexpansive bijection of it onto itself is an isometry; every totally bounded metric space is plastic (Freudenthal–Hurewicz 1936), and Cascales, Kadets, Orihuela and Wingler (2016) asked whether the closed unit ball of every real Banach space is plastic. For the sequence space c₀, Leo (2022) proved plasticity of the unit ball under the extra hypothesis that the inverse map is continuous; the project's earlier results, all unpublished, covered c₀(Γ) itself without that hypothesis (the earlier c0 mission), smooth strictly convex blocks of any finite dimension and strictly convex planes, with scalars beside them, ℓ¹ₙ blocks of bounded dimension, and polygonal planes, also beside discs. This mission formalizes a proof that the closed unit ball of every c₀ sum of real spaces of dimension at most two is plastic, for arbitrary index sets and arbitrary norms on the blocks, together with the two-space statement that every nonexpansive bijection between the balls of two such sums is an isometry. The results come from an unpublished research project on the plasticity problem.

Setting

For a family (Ei)i∈I(E_i)_{i\in I}(Ei​)i∈I​ of real normed spaces, the c0c_0c0​ sum c0(I;Ei)c_0(I;E_i)c0​(I;Ei​) consists of the families x=(xi)x=(x_i)x=(xi​) with xi∈Eix_i\in E_ixi​∈Ei​ and ∥xi∥→0\|x_i\|\to0∥xi​∥→0 along the cofinite filter, with the norm ∥x∥=sup⁡i∥xi∥\|x\|=\sup_i\|x_i\|∥x∥=supi​∥xi​∥. Its closed unit ball is B={x:∥x∥≤1}B=\{x:\|x\|\le1\}B={x:∥x∥≤1}. The blocks here have dimension at most two: zero, the real line, or a real plane with any norm, whose unit ball may be a parallelogram, a polygon, a disc, or have flat edges and curved arcs in any combination, with no uniformity over III.

Target

(CUB109)f ⁣:Bc0(I;Ei)→Bc0(K;Ek′) a nonexpansive bijection, dim⁡Ei,dim⁡Ek′≤2 ⟹ f is an isometry.\text{(CUB109)}\quad f\colon B_{c_0(I;E_i)}\to B_{c_0(K;E'_k)}\ \text{a nonexpansive bijection},\ \dim E_i,\dim E'_k\le2\ \Longrightarrow\ f\ \text{is an isometry.}(CUB109)f:Bc0​(I;Ei​)​→Bc0​(K;Ek′​)​ a nonexpansive bijection, dimEi​,dimEk′​≤2 ⟹ f is an isometry. (goal)the closed unit ball of c0(I;Ei) is plastic whenever every Ei has dimension at most two.\text{(goal)}\quad \text{the closed unit ball of } c_0(I;E_i) \text{ is plastic whenever every } E_i \text{ has dimension at most two.}(goal)the closed unit ball of c0​(I;Ei​) is plastic whenever every Ei​ has dimension at most two.

For finite index sets the balls are finite-dimensional, and both statements are covered by Zavarzina's theorem for finite-dimensional targets (Ann. Funct. Anal. 9 (2018), Theorem 3.8); the content is the infinite case.

Significance

The result. It settles plasticity for all c₀ sums of blocks of dimension at most two. It gives the first infinite c₀ sums in which scalar coordinates sit beside polygons or other planes that are not strictly convex, and the first non-polygonal planes that are not strictly convex (a curved ball with two edges meeting at a corner, or with countably many extreme points). Its proof shows that nonexpansive bijections between such balls are block-diagonal linear isometries, with scalar blocks going to scalar blocks after each parallelogram plane is split into two scalar coordinates.

Formalizing it. The proofs exist only in the project's notes and were checked by AI referees; a machine-checked proof is the independent confirmation sought. Known inputs available in this environment through earlier missions are invariance of domain, the Freudenthal–Hurewicz theorem and Brouwer's fixed-point theorem; Baire's theorem, Krein–Milman and Mazur–Ulam are in Mathlib.

Difficulty

For infinite index sets the ball is not compact, its unit sphere has large flat faces, and no regularity of the inverse map is assumed. The planar geometry is the bulk: covers of a planar ball by three translates near corners where two edges meet, an extreme lens and a far-comparison estimate at extreme points where the norm is curved, and the linearization of an extreme-point correspondence between two different planes from a single radial inequality. The c₀ part must match blocks, exclude scalar coordinates that feed planar blocks, and exclude the collapse of a block by a two-lift argument.

Formalization scope

Real scalars, arbitrary index sets (no countability or nonemptiness assumed), arbitrary norms on the blocks. The ℓ∞\ell_\inftyℓ∞​ sum is Mathlib's lp E ⊤; the c₀ sum is the submodule c0Sum E of it (definition Plasticity_C0Sum), with its subspace norm. "Dimension at most two" is Module.rank ℝ (E i) ≤ 2, which excludes infinite-dimensional blocks. The goal uses HasPlasticUnitBall (definitions Plasticity_Basic); the two-space theorem is stated for functions between the subtypes Metric.closedBall (0 : c0Sum E) 1, with LipschitzWith 1 and Function.Bijective.

13 thms1 active userReviewed
🏆Completed
Graph Theory·Captain: marwahaha

OpenAI Ten Proofs 10: Extremal graph counterexamplesResearch Paper

Extremal graph counterexamples, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

Write ex⁡(n,F)\operatorname{ex}(n,F)ex(n,F) for the maximum number of edges in an nnn-vertex simple graph containing no subgraph copy of FFF, with value 000 if there is no eligible graph; a copy is an injective edge-preserving map and need not be induced. For a finite family F\mathcal FF of finite simple graphs, each encoded on {0,…,q−1}\{0,\ldots,q-1\}{0,…,q−1} for its own q∈Nq\in\mathbb Nq∈N, let EF(n)E_{\mathcal F}(n)EF​(n) be the maximum edge count over simple graphs on {0,…,n−1}\{0,\ldots,n-1\}{0,…,n−1} containing no copy of any member of F\mathcal FF, again taking 000 for an empty collection. There exist a nonempty such family F\mathcal FF and real constants c,C>0c,C>0c,C>0 such that every member is connected, bipartite, and not acyclic; for each F∈FF\in\mathcal FF∈F, cn4/3≤ex⁡(n,F)c n^{4/3}\le\operatorname{ex}(n,F)cn4/3≤ex(n,F) for all sufficiently large natural nnn, with a threshold that may depend on FFF; for every n∈Nn\in\mathbb Nn∈N and every simple graph GGG on {0,…,n−1}\{0,\ldots,n-1\}{0,…,n−1} containing no copy of any member, ∣E(G)∣16≤Cn21|E(G)|^{16}\le C n^{21}∣E(G)∣16≤Cn21; and for every n∈Nn\in\mathbb Nn∈N, EF(n)16≤Cn21E_{\mathcal F}(n)^{16}\le C n^{21}EF​(n)16≤Cn21. These last two bounds use the same CCC and include n=0n=0n=0. The conclusions also include 0<1/480<1/480<1/48 and 21/16=4/3−1/4821/16=4/3-1/4821/16=4/3−1/48, as equalities and inequalities of real numbers. No member F∈FF\in\mathcal FF∈F and real constant D>0D>0D>0 satisfy ex⁡(n,F)≤DEF(n)\operatorname{ex}(n,F)\le D E_{\mathcal F}(n)ex(n,F)≤DEF​(n) for all sufficiently large nnn. Moreover, the assertion that every nonempty finite family of finite simple graphs whose members each contain a cycle admits such a member and constant is false.

Additional targets:

  • Asymptotic separation for a noncompact graph family.
  • Failure of compactness for cyclic graph families.
  • Two-degenerate graph with extremal exponent above 3/2.
  • Failure of the bipartite degeneracy extremal bound.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, J_CompactnessConjecture.json, J_TwoDegenerateGraphs.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

6 thms1 active userReviewed
🏆Completed
Graph Theory·Captain: marwahaha

OpenAI Ten Proofs 09: Multicolor triangle Ramsey numbersResearch Paper

Multicolor triangle Ramsey numbers, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

For each k∈Nk\in\mathbb Nk∈N, let R(k)R(k)R(k) be the infimum in N\mathbb NN of the integers nnn such that every labeling of the edges of the complete simple graph on {0,…,n−1}\{0,\ldots,n-1\}{0,…,n−1} by kkk colors has a monochromatic triangle; equivalently, no such labeling has every color graph free of a three-vertex clique. This is the least such nnn when the set is nonempty, with infimum 000 for an empty set. Both of the following hold: for every integer k≥2k\ge 2k≥2, (16e38 k1/3log⁡k)k≤R(k)\left(\frac{1}{6e^{38}}\,\frac{k^{1/3}}{\log k}\right)^k\le R(k)(6e381​logkk1/3​)k≤R(k), where all quantities in the inequality are real; and R(k)1/k→+∞R(k)^{1/k}\to+\inftyR(k)1/k→+∞ as k→∞k\to\inftyk→∞, meaning that for each real MMM there is K∈NK\in\mathbb NK∈N such that R(k)1/k≥MR(k)^{1/k}\ge MR(k)1/k≥M whenever k≥Kk\ge Kk≥K. The root sequence is defined also at k=0k=0k=0 using real division 1/0=01/0=01/0=0, so that term equals 111 and does not affect the limit.

Additional targets:

  • Divergence of multicolor triangle Ramsey roots.
  • Eventual logarithmic Ramsey coefficient bounds.
  • Logarithmic Ramsey growth has order k log k.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, I_MulticolorTriangleRamsey.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

5 thms1 active userReviewed
🏆Completed
Discrete Geometry·Captain: marwahaha

OpenAI Ten Proofs 08: Ehrhart volume inequalityResearch Paper

Ehrhart volume inequality, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

Let nnn be any positive natural number and S⊆RnS\subseteq\mathbb R^nS⊆Rn any convex compact set with nonempty interior. Write V(S)V(S)V(S) for its Lebesgue measure converted from [0,∞][0,\infty][0,∞] to a real number, and define its barycenter as V(S)−1∫Sx dxV(S)^{-1}\int_S x\,dxV(S)−1∫S​xdx. The conversion sends infinite measure to zero and real inversion is total, but these hypotheses make V(S)V(S)V(S) finite and positive. If this barycenter is the zero vector and {z∈Zn:z∈int⁡S}={0}\{z\in\mathbb Z^n:z\in\operatorname{int}S\}=\{0\}{z∈Zn:z∈intS}={0}, then V(S)≤(n+1)n/n!V(S)\leq(n+1)^n/n!V(S)≤(n+1)n/n!. The lattice condition says both that the origin lies in the interior and that no other integer vector does. The volume in this inequality is the real Lebesgue volume itself.

Additional targets:

  • Existence of a centered body attaining the volume constant.
  • Zero barycenter of the explicitly transformed standard simplex.
  • Exact volume of the explicitly transformed standard simplex.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, F_EhrhartVolumeInequality.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

5 thms1 active userReviewed
🏆Completed
Complexity TheoryDiscrete Geometry·Captain: marwahaha

OpenAI Ten Proofs 07: Hardness of the closest vector problemResearch Paper

Hardness of the closest vector problem, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

For every Boolean language AAA of finite bit strings for which there exist a polynomial P∈N[X]P\in\mathbb N[X]P∈N[X] and a deterministic polynomial-time Boolean verifier VVV satisfying A(x)=trueA(x)=\mathrm{true}A(x)=true if and only if there is a bit-string certificate ccc with ∣c∣≤P(∣x∣)|c|\le P(|x|)∣c∣≤P(∣x∣) and V(x,c)=trueV(x,c)=\mathrm{true}V(x,c)=true, there exists a total deterministic polynomial-time map fff on bit strings sending every xxx with A(x)=trueA(x)=\mathrm{true}A(x)=true into the following YES set and every xxx with A(x)=falseA(x)=\mathrm{false}A(x)=false into the following NO set. An instance consists of a natural dimension n>0n>0n>0, an integer matrix B∈Zn×nB\in\mathbb Z^{n\times n}B∈Zn×n with det⁡B≠0\det B\ne0detB=0, a target t∈Qnt\in\mathbb Q^nt∈Qn all of whose coordinates are integers, and a rational radius r>0r>0r>0. It is in YES exactly when some z∈Znz\in\mathbb Z^nz∈Zn satisfies ∑i=0n−1((Bz)i−ti)2≤r2\sum_{i=0}^{n-1}((Bz)_i-t_i)^2\le r^2∑i=0n−1​((Bz)i​−ti​)2≤r2, and in NO exactly when every z∈Znz\in\mathbb Z^nz∈Zn satisfies (n1/400r)2<∑i=0n−1((Bz)i−ti)2(n^{1/400}r)^2<\sum_{i=0}^{n-1}((Bz)_i-t_i)^2(n1/400r)2<∑i=0n−1​((Bz)i​−ti​)2. The sets consist of the exact encoded instance strings, formed by concatenating the encodings of nnn, rrr, the target coordinates in order, and the matrix entries in row-major order. Each scalar is encoded by taking its library natural-number code, applying the library's natural-number-to-bit-string encoding to get a word www, and prefixing www with ∣w∣|w|∣w∣ true bits followed by one false bit. Strings without such a valid encoded instance, and instances satisfying neither distance condition, are outside both sets; dimension one is included. Polynomial time is witnessed in the library's TM2 machine model, using its product encoding of Boolean lists for verifier input, its Boolean output encoding for the verifier, and identity encodings for the reduction's input and output.

Additional targets:

  • NP-hardness of binary nearest codeword with gap n^(1/200).
  • NP-hardness of feasible binary syndrome decoding with gap n^(1/200).
  • NP-hardness of rational finite-p lattice distance with gap n^(1/(200p)).

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, H_GapCVP.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

5 thms1 active userReviewed
🏆Completed
Complexity Theory·Captain: marwahaha

OpenAI Ten Proofs 05: Arithmetic formula lower bounds for the permanentResearch Paper

Arithmetic formula lower bounds for the permanent, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

For every natural number n≥32n\ge32n≥32 and every finite arithmetic formula fff whose leaves are variables xijx_{ij}xij​, 0≤i,j<n0\le i,j<n0≤i,j<n, or arbitrary complex constants and whose binary operations are addition, subtraction, multiplication, and division, assume that every divisor subformula evaluates to a nonzero element of the fraction field of C[xij]\mathbb C[x_{ij}]C[xij​] and that the value of fff in this fraction field equals the polynomial per⁡n=∑σ∈Sn∏i=0n−1xi,σ(i)\operatorname{per}_n=\sum_{\sigma\in S_n}\prod_{i=0}^{n-1}x_{i,\sigma(i)}pern​=∑σ∈Sn​​∏i=0n−1​xi,σ(i)​ under the canonical inclusion. Then the number V(f)V(f)V(f) of variable-leaf occurrences satisfies n4/(192log⁡2n)≤V(f)n^4/(192\log_2 n)\le V(f)n4/(192log2​n)≤V(f), with both sides viewed as real numbers. Repeated occurrences are counted separately, constants contribute zero, and the leaves of both operands of each operation, including division, are counted. Nonzero divisors are required as rational functions, not at every numerical substitution.

Additional targets:

  • Variable-leaf lower bound for division-free formulas computing the permanent.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, C_PermanentFormulaLowerBound.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

3 thms1 active userReviewed
🏆Completed
Functional AnalysisGroup Theory·Captain: marwahaha

OpenAI Ten Proofs 04: Counterexamples to Connes rigidityResearch Paper

Counterexamples to Connes rigidity, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

There exist a countable group Λ\LambdaΛ and a sequence of countable groups (Γn)n∈N(\Gamma_n)_{n\in\mathbb N}(Γn​)n∈N​, indexed also at n=0n=0n=0, such that all of them are finitely generated and infinite, every conjugacy class {xgx−1:x∈G}\{xgx^{-1}:x\in G\}{xgx−1:x∈G} of a nonidentity element in each such group GGG is infinite, and every such group has property T. For every nnn, L(Γn)L(\Gamma_n)L(Γn​) is isomorphic to L(Λ)L(\Lambda)L(Λ) as specified below, and for every m,nm,nm,n, including m=nm=nm=n, L(Γm)L(\Gamma_m)L(Γm​) is isomorphic to L(Γn)L(\Gamma_n)L(Γn​) in the same sense. If m≠nm\ne nm=n, there is no group isomorphism Γm≅Γn\Gamma_m\cong\Gamma_nΓm​≅Γn​, and for every nnn there is no group isomorphism Λ≅Γn\Lambda\cong\Gamma_nΛ≅Γn​. For each group GGG concerned, property T means that, for every complete complex inner-product space HHH and every homomorphism π:G→U(H)\pi:G\to U(H)π:G→U(H), if for every finite K⊆GK\subseteq GK⊆G and every real ε>0\varepsilon>0ε>0 there is a vector ξ∈H\xi\in Hξ∈H with ∥ξ∥=1\|\xi\|=1∥ξ∥=1 and ∥π(g)ξ−ξ∥<ε\|\pi(g)\xi-\xi\|<\varepsilon∥π(g)ξ−ξ∥<ε for all g∈Kg\in Kg∈K, then there is a nonzero vector fixed by every π(g)\pi(g)π(g). Here L(G)L(G)L(G) is the double commutant, inside the bounded complex-linear operators on ℓ2(G)\ell^2(G)ℓ2(G), of the left translations (λgf)(h)=f(g−1h)(\lambda_g f)(h)=f(g^{-1}h)(λg​f)(h)=f(g−1h), and τG(a)=⟨δ1,aδ1⟩\tau_G(a)=\langle\delta_1,a\delta_1\rangleτG​(a)=⟨δ1​,aδ1​⟩. An asserted isomorphism of these tracial algebras is a complex ∗*∗-algebra equivalence preserving τ\tauτ such that both it and its inverse preserve every existing supremum of any set of self-adjoint idempotents, with projection order q≤pq\le pq≤p defined by qp=qqp=qqp=q.

Additional targets:

  • Two nonisomorphic finitely generated property T ICC groups with isomorphic tracial group algebras.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, E_ConnesRigidity.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

3 thms1 active userReviewed
🏆Completed
Group Theory·Captain: marwahaha

OpenAI Ten Proofs 03: A finitely presented non-sofic groupResearch Paper

A finitely presented non-sofic group, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

There exist a set GGG and a group structure on GGG such that GGG has a finite presentation and is not sofic in the following precise sense: there are a finite subset F⊆GF\subseteq GF⊆G and a real number 0<ε<10<\varepsilon<10<ε<1 for which no positive integer ddd and map σ:G→Sym⁡({0,…,d−1})\sigma:G\to\operatorname{Sym}(\{0,\ldots,d-1\})σ:G→Sym({0,…,d−1}) with σ(1)=id\sigma(1)=\mathrm{id}σ(1)=id simultaneously satisfy dH(σ(gh),σ(g)σ(h))<εd_H(\sigma(gh),\sigma(g)\sigma(h))<\varepsilondH​(σ(gh),σ(g)σ(h))<ε for every g,h∈Fg,h\in Fg,h∈F and 1−ε<dH(σ(g),id)1-\varepsilon<d_H(\sigma(g),\mathrm{id})1−ε<dH​(σ(g),id) for every g∈Fg\in Fg∈F with g≠1g\ne1g=1. Here dH(p,q)=∣{i:p(i)≠q(i)}∣/dd_H(p,q)=|\{i:p(i)\ne q(i)\}|/ddH​(p,q)=∣{i:p(i)=q(i)}∣/d is normalized Hamming distance; σ\sigmaσ is defined on all of GGG and is not assumed to be a homomorphism. The finite subsets in the defining sofic approximation property include the empty subset, and the permutation sets are required to be nonempty.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, D_NonSoficGroup.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

2 thms1 active userReviewed
🏆Completed
Information Theory·Captain: marwahaha

OpenAI Ten Proofs 02: Binary and spherical codesResearch Paper

Binary and spherical codes, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

For every real δ\deltaδ with 0<δ<1/20<\delta<1/20<δ<1/2, the following strict inequality holds. Write h(x)=−xlog⁡2x−(1−x)log⁡2(1−x)h(x)=-x\log_2x-(1-x)\log_2(1-x)h(x)=−xlog2​x−(1−x)log2​(1−x), with the total-real logarithm convention log⁡20=0\log_2 0=0log2​0=0. Let A(n,k)A(n,k)A(n,k) be the maximum cardinality of a finite subset of {0,1}n\{0,1\}^n{0,1}n in which every two distinct words differ in at least kkk coordinates, and put R(δ)=lim sup⁡n→∞log⁡2A(n,⌈δn⌉)/nR(\delta)=\limsup_{n\to\infty}\log_2 A(n,\lceil\delta n\rceil)/nR(δ)=limsupn→∞​log2​A(n,⌈δn⌉)/n. Empty codes are permitted in the maximum; the n=0n=0n=0 sequence term is zero by total real division. Define g(v)=h((1−1−v)/2)g(v)=h((1-\sqrt{1-v})/2)g(v)=h((1−1−v​)/2) and M(δ)=inf⁡0≤t≤1−2δ{1+g(t2)−g(t2+2δt+2δ)}M(\delta)=\inf_{0\leq t\leq1-2\delta}\{1+g(t^2)-g(t^2+2\delta t+2\delta)\}M(δ)=inf0≤t≤1−2δ​{1+g(t2)−g(t2+2δt+2δ)}, a real infimum. Then R(δ)<M(δ)R(\delta)<M(\delta)R(δ)<M(δ).

Additional targets:

  • Binary-code rate is strictly below the classical entropy expression.
  • Positive gap below the classical binary-code rate expression.
  • Binary-code rate is bounded by the combined variational infimum.
  • The combined variational rate is strictly below the defined MRRW rate.
  • Positive gap below the defined MRRW binary-code rate.
  • Binary-code rate bound and strict improvement of the MRRW rate.
  • Finite spherical-code bounds and the closed hierarchy rate bound.
  • Strict descent of spherical-code hierarchy rates and localized rates.
  • Eventual kissing-number bound with exponent 0.39661.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, B_BinaryCodes.json, B_SphericalCodes.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

11 thms1 active userReviewed
🏆Completed
Discrete Geometry·Captain: marwahaha

OpenAI Ten Proofs 01: High-dimensional sphere packingResearch Paper

High-dimensional sphere packing, from the OpenAI Ten Proofs formalization. The source already contains machine-checked proofs; this mission organizes its headline result and additional Comparator targets for reuse.

For each natural number ddd, let Fd\mathcal F_dFd​ consist of complex-valued Schwartz functions on Euclidean Rd\mathbb R^dRd whose values and Fourier-transform values are real, with f^(ξ)≥0\widehat f(\xi)\geq0f​(ξ)≥0 for every ξ\xiξ, f^(0)>0\widehat f(0)>0f​(0)>0, and f(x)≤0f(x)\leq0f(x)≤0 whenever ∥x∥≥1\|x\|\geq1∥x∥≥1; radiality is not required. Put q(f)=f(0)/f^(0)q(f)=f(0)/\widehat f(0)q(f)=f(0)/f​(0), Vd=πd/2/Γ(d/2+1)V_d=\pi^{d/2}/\Gamma(d/2+1)Vd​=πd/2/Γ(d/2+1), and Ld=(Vd/2d)inf⁡f∈Fdq(f)L_d=(V_d/2^d)\inf_{f\in\mathcal F_d}q(f)Ld​=(Vd​/2d)inff∈Fd​​q(f), where the infimum is taken in R\mathbb RR. Put Ad=inf⁡f∈Fdq(f)1/dA_d=\inf_{f\in\mathcal F_d}q(f)^{1/d}Ad​=inff∈Fd​​q(f)1/d, B=e/(2π)B=\sqrt{e/(2\pi)}B=e/(2π)​, and c=12log⁡2(2π/e)c=\tfrac12\log_2(2\pi/e)c=21​log2​(2π/e). The assertion is the conjunction of the following ten claims: Ad/d→1/πA_d/\sqrt d\to1/\piAd​/d​→1/π; there exists a real sequence ud→0u_d\to0ud​→0 such that Ad=(1/π+ud)dA_d=(1/\pi+u_d)\sqrt dAd​=(1/π+ud​)d​ for every d>0d>0d>0; Ld1/d→BL_d^{1/d}\to BLd1/d​→B; (log⁡Ld)/d→12log⁡(e/(2π))(\log L_d)/d\to\tfrac12\log(e/(2\pi))(logLd​)/d→21​log(e/(2π)); there exists a real sequence vd→0v_d\to0vd​→0 such that Ld=(B+vd)dL_d=(B+v_d)^dLd​=(B+vd​)d for all sufficiently large ddd; there exists a real sequence δd→0\delta_d\to0δd​→0, nonnegative for every natural ddd, such that for all sufficiently large ddd and every f∈Fdf\in\mathcal F_df∈Fd​, (2d/Vd)(B−δd)d≤q(f)(2^d/V_d)(B-\delta_d)^d\leq q(f)(2d/Vd​)(B−δd​)d≤q(f); c>0c>0c>0; 0.604400544291677695341677307053<c<0.6044005442916776953416773070540.604400544291677695341677307053<c<0.6044005442916776953416773070540.604400544291677695341677307053<c<0.604400544291677695341677307054; (log⁡2Ld)/d→−c(\log_2 L_d)/d\to-c(log2​Ld​)/d→−c; and there exists a real sequence wd→0w_d\to0wd​→0 such that Ld=2−(c+wd)dL_d=2^{-(c+w_d)d}Ld​=2−(c+wd​)d for all sufficiently large ddd. Each limit is along natural dimensions tending to infinity, and the four existentially quantified error sequences need not coincide. The sequences are defined also at d=0d=0d=0 using total real operations, in particular 0−1=00^{-1}=00−1=0 and division by zero equal to zero; the displayed 1/d1/d1/d powers denote those real powers.

Additional targets:

  • Exact root limit of the full Cohn–Elkies program.
  • Exact binary logarithmic rate of the full Cohn–Elkies program.
  • Sphere-packing density bound with a vanishing root error.

The formalization uses Lean 4.33.1 with Mathlib revision 0df444a360eaa60ab8c11dca51a86af692955474. Its goal and milestone statements retain the validated source statements and their conventions.

Sources: Lean formalization, A_SpherePacking.json.

Planned collection: OAI Ten Proofs (oai-ten-proofs).

5 thms1 active userReviewed
Quantum Information·Captain: Goku

Everything You Always Wanted to Know About LOCC (But Were Afraid to Ask)Research Paper

Motivation

In this paper we study the subset of generalized quantum measurements on finite dimensional systems known as local operations and classical communication (LOCC). While LOCC emerges as the natural class of operations in many important quantum information tasks, its mathematical structure is complex and difficult to characterize. Here we provide a precise description of LOCC and related operational classes in terms of quantum instruments. Our formalism captures both finite round protocols as well as those that utilize an unbounded number of communication rounds. While the set of LOCC is not topologically closed, we show that finite round LOCC constitutes a compact subset of quantum operations. Additionally we show the existence of an open ball around the completely depolarizing map that consists entirely of LOCC implementable maps. Finally, we demonstrate a two-qubit map whose action can be approached arbitrarily close using LOCC, but nevertheless cannot be implemented perfectly.

This mission is the statement-level formalization of Everything You Always Wanted to Know About LOCC (But Were Afraid to Ask) (arXiv:1210.4583v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

12 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is An explicit two-qubit instrument in the closure of LOCC but outside LOCC (Abstract; §§4.1,4.3, Eqs.(10)–(12), PDF p. 1). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

1 results of the paper are not stated yet, because the library lacks an interface they need:

  • Lemma 2, Eq.(20); Appendix B pp.19–21: A source-correct strict-decrease domain, or a definition of nontrivial measurement depending on the input state. (source-ambiguity)

Selected references

  • Everything You Always Wanted to Know About LOCC (But Were Afraid to Ask), arXiv:1210.4583v2, https://arxiv.org/abs/1210.4583v2
18 thms1 active userReviewed
Quantum Information·Captain: Goku

Lie-Semigroup Structures for Reachability and Control of Open Quantum SystemsResearch Paper

Motivation

In view of controlling finite dimensional open quantum systems, we provide a unified Lie-semigroup framework describing the structure of completely positive trace-preserving maps. It allows (i) to identify the Kossakowski-Lindblad generators as the Lie wedge of a subsemigroup, (ii) to link properties of Lie semigroups such as divisibility with Markov properties of quantum channels, and (iii) to characterise reachable sets and controllability in open systems. We elucidate when time-optimal controls derived for the analogous closed system already give good fidelities in open systems and when a more detailed knowledge of the open system (e.g., in terms of the parameters of its Kossakowski-Lindblad master equation) is actually required for state-of-the-art optimal-control algorithms. -- As an outlook, we sketch the structure of a new, potentially more efficient numerical approach explicitly making use of the corresponding Lie wedge.

This mission is the statement-level formalization of Lie-Semigroup Structures for Reachability and Control of Open Quantum Systems (arXiv:0811.3906v4). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

5 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is The generated Markovian semigroup has the full channel tangent wedge (Theorem III.3, PDF p. 8). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

30 results of the paper are not stated yet, because the library lacks an interface they need:

  • Lemma II.1: Accepted source-matched theorem for Lemma II.1 (provenance boundary) (hard)
  • Theorem II.1: Missing Ad_K invariance of c (source-ambiguity)
  • Proposition II.1: Accepted source-matched theorem for Proposition II.1 (provenance boundary) (hard)
  • Proposition II.2: Accepted source-matched theorem for Proposition II.2 (provenance boundary) (hard)
  • Theorem II.2: Accepted source-matched theorem for Theorem II.2 (provenance boundary) (hard)
  • Theorem II.3: Accepted source-matched theorem for Theorem II.3 (provenance boundary) (hard)
  • Theorem II.4: Accepted source-matched theorem for Theorem II.4 (provenance boundary) (hard)
  • Theorem II.5: Accepted source-matched theorem for Theorem II.5 (provenance boundary) (hard)
  • Theorem II.6: Accepted source-matched theorem for Theorem II.6 (provenance boundary) (hard)
  • Corollary II.1: Accepted source-matched theorem for Corollary II.1 (provenance boundary) (hard)
  • Corollary II.2: Accepted source-matched theorem for Corollary II.2 (provenance boundary) (hard)
  • Theorem III.1: Independent x/y control indexing and original-result provenance (source-ambiguity)
  • Theorem III.2: Accepted source-matched theorem for Theorem III.2 (provenance boundary) (hard)
  • Proposition III.1: Accepted source-matched theorem for Proposition III.1 (provenance boundary) (hard)
  • Theorem III.4: Dimension-qualified nondivisibility theorem (source-ambiguity)
  • Corollary III.2: Dimension-qualified failure of Lie-subsemigroup generation (source-ambiguity)
  • Corollary III.3: Dimension-qualified local failures and non-semialgebra wedge (source-ambiguity)
  • Corollary III.4: Nonvacuous fixed-semigroup identity neighborhood and generator signs (source-ambiguity)
  • Corollary III.5: Endpoint representations versus one fixed exponential trajectory (source-ambiguity)
  • Resume: A specified genericity space and canonical dissipator gauge (source-ambiguity)
  • Proposition III.2: Nontrivial homogeneous space for the smallest-positive-scaling conclusion (source-ambiguity)
  • Corollary III.6: Canonical dissipator gauge and a definition of generic (source-ambiguity)
  • Reachability-product: Accepted source-matched theorem for Reachability-product (provenance boundary) (hard)
  • Remark II.1: Accepted source-matched theorem for Remark II.1 (provenance boundary) (hard)
  • Remark II.3: Accepted source-matched theorem for Remark II.3 (provenance boundary) (hard)
  • Trace-norm-contraction: Accepted source-matched theorem for Trace-norm-contraction (provenance boundary) (hard)
  • Purity-unitality: Accepted source-matched theorem for Purity-unitality (provenance boundary) (hard)
  • Remark III.1: Accepted source-matched theorem for Remark III.1 (provenance boundary) (hard)
  • Markovian-stratification: Dimension scope and explicit interior/strict-inclusion witnesses (source-ambiguity)
  • Scalar-decay-optimal-time: Quantitative almost-uniform decay and attained argmax domain (source-ambiguity)

Selected references

  • Lie-Semigroup Structures for Reachability and Control of Open Quantum Systems, arXiv:0811.3906v4, https://arxiv.org/abs/0811.3906v4
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Quantum Information·Captain: Goku

Classical Capacity of Single-Mode Bosonic Gaussian ChannelsResearch Paper

Motivation

The classical capacity of a noisy optical channel is the maximum rate at which information can be transmitted reliably, given a constraint on the mean input energy. For the ubiquitous bosonic Gaussian channels, which include standard models of loss and noise in fibre and free-space optical links, determining this rate requires addressing whether entanglement between channel uses or non-Gaussian signals can outperform Gaussian encodings. More precisely, the question is whether the energy-constrained Holevo information is additive across arbitrarily many channel uses and coincides with its Gaussian counterpart. We answer these fundamental questions in the affirmative for every single-mode bosonic Gaussian channel at every input energy. Namely, we prove that independently prepared Gaussian states with Gaussian-distributed random displacements achieve the capacity, including in the low-energy regime where squeezing the signals competes with encoding information in their displacement. Our proof connects an entanglement inequality to a sharp, additive lower bound on output entropy. We then characterise communication above capacity: under a strict total photon-number cutoff, the probability of correct decoding decreases exponentially with the number of channel uses, and we derive explicit bounds on the decay exponent. When only the mean photon number is constrained, a simple energy-rescaling formula determines exactly the entire asymptotic rate--error trade-off: the capacity at mean photon number NNN and allowed average decoding error εεε equals the vanishing-error capacity at mean photon number N/(1−ε)N/(1-ε)N/(1−ε). Together, these results identify the ultimate limits of classical communication for some of the most fundamental models of optical communication. △ Less

This mission is the statement-level formalization of Classical Capacity of Single-Mode Bosonic Gaussian Channels (arXiv:2610.22308v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

2 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Affine envelope and joint convexity of the moment-resolved entropy (Eq. (18), PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

27 results of the paper are not stated yet, because the library lacks an interface they need:

  • Corollary 3 (pp.5,12), resolving the p.1 paper-result seed: capacities and water-filling: bosonic channels, arbitrary probability ensembles, Gaussian displacement ensembles, and operational classical capacity (hard)
  • Theorem 1: output entropy from second moments: finite-energy Fock states, raw quadrature quadratic-form moments, von Neumann entropy, and squeezed vacua (hard)
  • Theorem 2: moment-resolved Gaussian optimality: continuous bosonic ensembles and product Gaussian displacement ensembles (hard)
  • Corollary 4: finite correlated blocks: passive Fock-space implementation of a common noise diagonalizer and repeated-block capacity (hard)
  • Unnumbered §IV: positive mode costs and marginal-gain rule: weighted-energy bosonic ensemble capacity and actual Gaussian Holevo energy functions (hard)
  • Unnumbered Eq.(22) and Appendix E.1: operational limit of chain memory channels: growing chain Gaussian channels and operational coding capacity along a nonidentical sequence (hard)
  • Proposition 5: tight Gaussian reference: infinite-dimensional relative entropy and a constructed optimal Gaussian reference (hard)
  • Unnumbered Eq.(24), Appendix F: uniqueness and quantitative stability: bosonic ensemble Holevo deficit, trace norm, marginals and Gaussian reference tensor powers (hard)
  • Theorem 6: exact nonzero-error capacity: operational nonzero-error capacity for bosonic mean-energy code sequences (hard)
  • Proposition 7: exponential cutoff strong converse: bosonic photon-cutoff codes and their operational capacity (hard)
  • Proposition 8: mixed-state affine entropy bound: mixed bosonic bipartite states and unbounded annihilation-operator quadratic forms (hard)
  • Lemma 9: quadrature-dependent dilation expectation: symplectic Fock unitaries, their Stinespring action, and quadrature-dependent quadratic-form expectations (hard)
  • Proposition 10: growing-memory converse and error trade-off: uniform Gaussian dilations and operational codes along growing memory blocks (hard)
  • Fact 11: Gaussification commutes with Gaussian channels: Gaussification as an actual normalized Gaussian Fock state with prescribed moments (hard)
  • Proposition 12: transfer from cutoff to mean energy: arbitrary bosonic-input channels, bounded decoding POVMs, and cutoff-code success supremum (hard)
  • Lemma 13: energy-preserving positive-filter coding inequality: Stinespring image filters and projective operator tensor norm on infinite Fock factors (hard)
  • Lemma 14: uniform exponential moments for symplectic unitaries: symplectic unitary tensor powers and extended nonnegative photon-exponential expectations (hard)
  • Proposition 15: approximating energy image filters: positive finite-rank energy-image filters and finite-local-support approximants on Fock tensor factors (hard)
  • Proposition 16: computable filter exponent: actual cutoff-code success exponent, Gaussian dilation constants and true capacity function (hard)
  • Proposition 17: explicit photon-tail bound: canonical Gaussian channel outputs on arbitrary cutoff states and decoding success (hard)
  • Lemma 18: output photon-number moments: extended output photon-number moments for arbitrary entangled cutoff Fock states (hard)
  • Proposition 19: converse for optimal Gaussian signal family: actual displaced squeezed Gaussian codewords and infinite-dimensional Petz Renyi expressions (hard)
  • Unnumbered Appendix B: energy-preserving canonical reduction: Fock implementations of input phase rotations and output symplectic transformations (hard)
  • Unnumbered G8: photon-subspace dimension and channel-independent bound: photon-subspace Hilbert dimension and channel-independent cutoff decoding success (hard)
  • Unnumbered H44: approach of the filter exponent to capacity: dilation-dependent H43 filter exponent using true operational Gaussian capacity (hard)
  • Unnumbered H45: weak photon tails: averaged photon-tail weight, actual cutoff-code supremum and vacuum-mixture code sequence (hard)
  • Unnumbered H46–H47: fixed multimode Gaussian channels: fixed finite-mode Gaussian channels and regularized operational bosonic capacity (hard)

Selected references

  • Classical Capacity of Single-Mode Bosonic Gaussian Channels, arXiv:2610.22308v1, https://arxiv.org/abs/2610.22308v1
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Quantum Information·Captain: Goku

Entanglement-breaking channels in infinite dimensionsResearch Paper

Motivation

We give a representation for entanglement-breaking channels in separable Hilbert space that generalizes the "Kraus decomposition with rank one operators" and use it to describe the complementary channels. We also give necessary and sufficient condition of entanglement-breaking for a general quantum Gaussian channel. Application of this condition to one-mode channels provides several new cases where the additivity conjecture holds in full generality.

This mission is the statement-level formalization of Entanglement-breaking channels in infinite dimensions (arXiv:0802.0235v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

4 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Radon–Nikodym representation of a POVM (Lemma 1: Radon–Nikodym representation of a POVM (9)–(10), PDF p. 3). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

18 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 2: Gaussian entanglement-breaking criterion and representation (30)–(31): Normal Gaussian trace-class channels, Gaussian states and trace-norm measure-and-prepare integral (hard)
  • Theorem 1: continuous densely defined rank-one representation (17)–(18): Measurable trace-class preparation from densely defined algebraic functionals (hard)
  • Proposition 1: sign of coherent information for (anti-)degradable channels: Genuine complementary trace-class channels and finite-entropy coherent information (hard)
  • Unnumbered: explicit Stinespring isometry and complementary kernel: Vector-valued L2 Stinespring realization and scalar integral-operator kernel (hard)
  • Example: spectral L2 measure-and-prepare channel and complementary Schur kernel: Canonical trace-class L2 diagonal and spectral measure-and-prepare map (hard)
  • Unnumbered: every entanglement-breaking channel is anti-degradable: Explicit entanglement-breaking antidegrading map on the full L2 environment trace class (hard)
  • Unnumbered: sharp Gaussian observable iff noise vanishes: Joint spectral measure of unbounded commuting quadratures with symplectic outcome transport (hard)
  • Proposition 2: covariant operator density of a nonsingular Gaussian observable: Gaussian trace-class seed state and displaced covariant operator density (hard)
  • Proposition 3: explicit Gaussian Naimark dilation (24)–(26): Gaussian ancillary Weyl system, normal partial-state evaluation and sharp joint spectral dilation (hard)
  • Unnumbered: complete positivity condition for Gaussian channel parameters (29): Normal trace-class realization of the Weyl channel characteristic law (hard)
  • Unnumbered: necessary PPT inequalities and Gaussian output PPT property (35): Partial transpose and Gaussian state law on a completed reference tensor product (hard)
  • Unnumbered: isotropic K gives a sharp-measurement c-q channel: Sharp quadrature PVM and displaced Gaussian preparation channel (hard)
  • Unnumbered claim: arbitrary sharp peaking around every outcome point: Correct outcome range in the arbitrary sharp-peaking claim (source-ambiguity)
  • Unnumbered: complete one-mode entanglement-breaking thresholds A, B1, B2, C, D: Actual canonical Gaussian channels and Gaussian unitary equivalence (hard)
  • Unnumbered: constrained chi-capacity additivity for the classified one-mode regimes: Extended constrained Holevo capacity for generalized ensembles and channel tensor products (hard)
  • Unnumbered: entanglement-breaking channels have zero quantum capacity: Operational unconstrained quantum capacity on separable trace-class channels (hard)
  • Unnumbered: energy-constrained tensor-power additivity and single-letter classical capacity (8): Formal spectral-energy constraints, tensor-power classical codes and extended constrained Holevo capacity on full trace-class channels (hard)
  • Unnumbered conditional discussion: Gaussian-optimizer capacity formula: Scope of the Gaussian optimizer conjecture used for operational capacity (source-ambiguity)

Selected references

  • Entanglement-breaking channels in infinite dimensions, arXiv:0802.0235v1, https://arxiv.org/abs/0802.0235v1
6 thms1 active userReviewed
Quantum Information·Captain: Goku

Mutual and coherent informations for infinite-dimensional quantum channelsResearch Paper

Motivation

The work is devoted to study of quantum mutual information and coherent information -- the two important characteristics of quantum communication channel. Appropriate definitions of these quantities in the infinite-dimensional case are given and their properties are studied in detail. Basic identities relating quantum mutual information and coherent information of a pair of complementary channels are proved. An unexpected continuity property of quantum mutual information and coherent information following from the above identities is observed. An upper bound for the coherent information is obtained.

This mission is the statement-level formalization of Mutual and coherent informations for infinite-dimensional quantum channels (arXiv:1004.2495v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

24 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Theorem 1: complementary-channel mutual-information identity (22) (Theorem 1: complementary-channel mutual-information identity (22), PDF p. 13). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Selected references

  • Mutual and coherent informations for infinite-dimensional quantum channels, arXiv:1004.2495v2, https://arxiv.org/abs/1004.2495v2
27 thms1 active userReviewed
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